Pragmatic 71: Off The Rails

18 March, 2016


Trains and roads look like they have lots in common but the trade-offs in signalling and network design are completely different, and horrendously inconsistent.

Transcript available
Welcome to pragmatic pragmatic is a discussion show contemplating the practical application of technology by exploring the real-world trade-offs we look at how great ideas are transformed into products and services can change our lives nothing is as simple as it seems pragmatic as part of the engineered network to support our shows including this one head over to our patron on page it's at GG or one word and for other great shows visit today on your host John GG and today I'm joined by Vic Hudson has gone back good diary today very good very good thank you arm today alike talk about trains trading delighted he had trains the trains when I was a child I had curtains and a bedspread match that were trains are cool migrating medium for me are as lovely CI I've always had a soft spot for trains and I had a request come in from the listener that wanted me to do an episode about trains and I had a good long hard think about what it is about trains that I i.e. I like so much I have a love hate thing for trying to be honest but I guess some young from Ivor I've been on trains on off arm for property 20 years now and is arm it's in different countries around the world are different countries are but a few different cities around the world like I've dived in the mines in Sydney done trams in Melbourne of Dunn are the trains in your in Brisbane obviously and are light rail in Calgary are mired been for a spin on the blast in Naas San Francisco yes so beloved mix of different things round the world and in trains of been I think a pivotal change in our in-house in Western culture in a 400 year hundred 200 years so I think trains are interesting but there's only so much there's a lot of talk about trains so I try narrows down the orbit arm and I also add that is armed as the point of interest that all the notes that I'm about to read this episode and in fact most of the episodes of pragmatic and causality were are created edited modified and the editing of a pod cast was done whilst travelling on a train to the writing I mentioned trains and trams should property discreetly clarify the difference arm trains like is in heavy rail trains are there big and heavy funnier and these mainly for freight as well as large numbers of passengers I really large like many many hundreds of passengers and they define by having dedicated tracks on the tracks only cross roads while an excellent railway crossing is right and that and actually share a road with other vehicle classes and mainly because they are very big very heavy and very dangerous so why keep separate and they utilise block signalling another maker sense later with a little bit more due to the longer braking distances and the and what. Quickly know don't stop and hurry know when they get move in case they move in say anyway sorta more about that later on and a multiple aspect signalling and all other good stuff trams on the other hand are in North America there are sometimes referred to as streetcar or a trolley trolley car are so well for some of our guileless streetcar I cannot really streetcar that the tram no streetcar whatever same difference ultimate so they travel on a combination of sort of exclusive access tracks like the heavy rail does but they also importantly share lines embedded within roadways yes you can drive behind tram or a tram can dry behind you and scare the Job what is out of you because at the age this enormous tram is about to drive right up your rear end anyway the mites open are yes light rail though are frequent in our first time are light rail is often implemented in sort of far similar ways sharing roadways and other vehicles but the difference of light rail is it sort of it more regularly carries higher passenger counts and it consists of multiple units connected together race trams are almost exclusively singular units so are light rail of course being like trams is slower and it utilises our traffic flow signalling again talk more about flow signalling later and allows multiple car multiple trains are light rail casts like going to stack up nose to tail that reduces network congestion but you get that limit the thing about trams that I found interesting was that trams were only used for public transports much later than heavy rail and originally no horse-drawn does back in the early 1800s but the first electric Tramway was opened in 1881 in Germany in that lecture felt and was built by Wernher von Stevens yet Mr Stevens are 90 find that funny because of course I spent a large chunk of my career programming Siemens PLCs yea Siemens seven 300 baby okay world's best plc send the flame lay a gate there I took some controls and programmers and they basically Siemens is the enemy Siemens is like some kind of poison and you can't understand how to program Siemens plc are all there to go funky with their OOB one in OB 35 and all that Gallagher Mac versus Windows urine Avril versus android cannot think kinda thing yeah is almost a year and is but statistically Siemens PLCs the world's most popular plc unless they were five years ago Dali since that's recently burning our sidetrack there go Siemens anyway so are some specific deep-fried of the highest level gig fired about the highest level beaver definitely is a gigabyte okay so the funny thing is that a lot of cities have both arm or just the heavy rail or a railing trams and different different year optimisations so some cities are used are the transfer shorthaul and trains for long haul and that's what Brisbane originally did but then of course the Rector trams out and you ultimately trams investor well premature around the world and I guess we should talk about the death of trams because in the US are there is an as Neville is an urban legend or as an actual conspiracy I'm not sure to be honest because I wasn't there but hey are regarding General Motors and diesel buses have you heard much about this one the army was National city lines that owned and operated several streetcar subsidiary I don't think I have heard this one but I have heard from some conspiracy theories about some of the car companies killing off like electric vehicles and stuff that's another topic for another day but hey are you so I'm assuming or talking about something similar yes we are absolutely and the thing is that there were there were actually worse our indictments over system better briefly are because it is interesting sometime between 1938 and 1950 streetcar is all around America were being replaced gradually by buses and even though nine corporations and seven individuals were indicted for and this is the quote from a judge of the time conspiring to acquire control of a number of transit companies forming a transportation monopoly" that was in 1947 but the problem with the whole theory behind that was that many many countries around the world also stopped using trams around about that time and the reasons simply came back to money the mass manufacture of buses and their associated therefore reduced running costs relative to electric trams just it simply made it difficult to financially justify something that was more niche arm and therefore more specialised operate and maintain like trams so you because you have to maintain roads for cars so putting a bus on the road is an incrementally small cost plus the bus the mass manufactured and the trams were highly specialised there were as many of them so if you look closely at most the tram systems around the world that are still operating condition today still servicing customers are all very heavily subsidised by the government and the reason they keep going it's for more than just economic reasons as was down to economic reasons that we wouldn't run their quieter they cause less pollution and I are receiving bad character to a city in an characters were something in a EEE I know I'm an engineer and space to think that but I do actually think that in the cable cars are still going SA is a tourist thing in San Francisco can you imagine San Francisco without cable cars and about you that just feels wrong to me doesn't feel feels like it did appear it would be a travesty of that ever happened at the very iconic image yet is iconic and having travelled on a cable car myself now I can I totally get why I think they're fantastic are just less nostalgia in me speaking that's okay anyway right so now we talk about trams in the not entire death of trams in the resurgence of light rail I guess a little bit but yes the light rail is making the resurgence arm I will focus on trains though because there's a lot more of them now I been taking Trainspotting I said before about 20 years now and I've done a little bit of work.not that much work belittled to work with Queensland Rail which is the Queensland Railway calm Corporation are and I was a subcontractor those many years ago now now seen their control system and have had many many many long conversations with signalling and rolling stock engineers over the years arm so why say rolling stocks are not sure if that's an Australian expression I don't think so arm because in our railway in Queensland Rail and most railway companies they do they have different divisions that I have arm the have track arm in the case were selected by the have overhead and then they'll have far rolling stock which take care of all the locomotives are carriages or stuffers rolling stock will rolling equipment on the rails arm and are then you have signalling so crucial Queensland Rail axiom really not sure that my guess my information how Queensland Rail is broken down inside is about 10 years out of date now is an old I guess and I don't guess I am anyway so yes about 10 years old but that's okay that's what used to be split up so anyway I spoke with signalling and rolling stock engineers predominantly so about a variety of ever met an overhead arm engineer or track engineer before because arm is heaven so in my hometown I grew up in Rockhampton and today my hometown there were two main professions when you graduate as an electrical engineer can go a worker Queensland Rail or you go work in the mines and are moving me naturally I didn't do either is that the country's Lego grew there some out here a serious option C aha I'm making an option C year later anyhow arm but then I came back to the so I was been fascinated by the train architecture and I don't mean the train physical architecture but I mean the network that travels on and I realise of onboarding traffic engineering and network engineering a little bit that is fascinating while back I think is so why my fascinated by it well see because in stucco train delayed many many many times and I certainly carriages my head pressed against the window looking outside trapped unable to escape and wondering what the heck is wrong why is the train not moving anyway so thought about it and I thought about what's wrong with the train train network architectures why the networks grew the way they have and that's what I want to focus on today I talk about how the train networks have grown changed evolved over the many many hundred years or so and also about how the signalling works and similar bottlenecks in some the restrictions because I think it's fascinating so it all begins when someone was to travel between two places in a town and they don't want to walk because they don't have a horse and they were sore feet on whether Ireland otherwise new fan dangled dumb order what sets you know what order thingies dams that have one of them either to really expand our Castilla that's it seat we don't have them right is going back hundred 50 years right so and because comply caddy because cabbies are an absolute rib often can't trust them either permit is mass murder so nevermind that way out and there was no over it was uber less candid by media all the so what am I gonna do our before they were buses I'd them out the mass transit solution was the train and obviously we talked about trams in light rail and heavy rail and all that I don't going into that again but yes survived acknowledge there are differences anyway so again heavy rail is mainly designed for moving around large numbers of people or large amounts of freight but because it's not so fast it won't handle acceleration or deceleration as well as light rail will so it's not such a good thing for a suburban network it's got lots of starting and stopping our light rubber the opposite which is what having never resurgence for the inner suburbs it's light faster quicker cheaper to build doesn't need as much ballast which is the year are although the rocks and the other stabilising arm are gosh the horizontal arm pillars that connect the rails together sleepers I should say gosh had it when I'm struggling for a work they get that was it you doesn't the overhead power lines therefore don't have to carry as much current so they're lighter again there cheaper so it's having never resurgence but I will talk about the different methods of pushing trains along either side is also the variance like A/C traction DC traction overhead power third rail power maglev heart if you answered a thing or hyperlinked if your Ellen mask which is totally crazy weird future cool stuff but that is naturally work yet it's a pipedream literally a pipe and anyway so there you go and it's a name own the pipe in the is keep dreaming of my work is if you can keep the vacuum movie whatever right when they when I pull off a copy impressed until Dennis disturbed an interesting idea appropriate exactly anyway so arm sorry a lot of you listening I doubt that's happening the game I will talk about the trade-offs of how wrong it was to put together so quickly as the terminology think what I say points and switch tracks do not talk about our excellent course I gotta change that train from one track to another track the liaison as a points in until about not outscoring a game of football or ping-pong with that what they are no identified sports for warily with a bowl and eyewear and of an invention called sports but that's all I know is that sports is a sport thing with sporting points anyhow right all stations versus expresses expresses and fast on aces that were directly I am digressing this is episode is becoming a constant digression they go ahead anyhow any hose who rails the groove are all alright are you a legend okay now that I'm totally focused can get no focus for one of the long homelessness and so as cities got larger and larger the trains in the city to develop a different set of design challenges you couldn't just keep adding more and more stations without suffering because the further out you went the more times the train would have to stop and that would mean that anyone got on would have to be put through more and more stops in order to get to where they want to go which was in the city so when train networks a small yellow star with a handful of stations are and the train stops everyone but then the gaps between the stations might be maybe two or 3 miles or kilometres apart let's say suddenly there's a new development of housing or a re-urbanisation in or a green space to get bulldozed by some jerk to make way for more houses and then you add more train stations in between the original train stations all you add a few more at the end of the line anyone commuting from under the other now is the slowdown stopwatch would get on and off get moving again every single station in between so it's time to think about express trains and act kinda solve some of the problems order because then there's different ways of dealing with express trains so the idea is you nominate either major or minor stations and you can run two or three classes of train stopping all stations stopping major stations or skipping sections of stations so the original train lines the problem is that they were designed for express travel they were designed for high maximum speed through the train stations and it takes time to accelerate to maximum speeds so in order to accommodate express trains they often had to do an upgrade of the train lines to make them smoother straighter flatter upgrade the points that you could travel through the points at high speeds so that the trains could basically realise the advantages or the full advantages of being an express train so because if you do that than the benefits of being express really would be fully fully realised but there's a problem with single tracks because a single track and carry one train in one section at one time and in the past railway companies and tight budget might install a single train line between all the stations but then the rout gets too long and once the frequency of the trains increases and the rout is so long it gets to a point at which the train physically has to travel from one end to the other and back again in less time than passengers are prepared to wait for the train to come back so what you do well you add a second train one heading inbound and one heading outbound soap to accommodate that you need nominate a place along the rout to have a split in the line where one train pulls over to let the other one pass and carry on his merry way again now in a suburban network you do that a train station because that usually we owe you got more real estate to work with but that unfortunately creates an interlock in the timetables so the inbound has the didn't wait for the outbound to arrive the change of appointment before they can continue and what happens if the train breaks down or it's late although the problem with the points so everybody setting everybody's very very pesky then I happy so what you do you add redundancy so we've now reached the point where the train networks look at installing two train tracks one for inbound trains and one outbound trains suddenly parallel by way yet exactly and this leads to a dual platform configurations of course originally have single train tracks single platform and that platform would handle both directions but now you got inbound and outbound are now one train platform is predominately for inbound trains the other is for outbound trains so that your platform configurations are train stations is is is this is becomes the standard now we have a crossover points and key places usually the entrances and the edges of each the train station sometimes between the train stations and allows the trains to jump from one line to the other if there's issues and then of course we have redundancy in a system and we have much better timetables with fewer interlocks in them and you might think done you know what the hands with solve the problem but you haven't because you still have a problem with express trains see in order to run an inbound express train you need to clear the track in front of it because if every train runs at a constant speed then we have to use the inbound track only because there's other trains going outbound and they have to meet their own timetable requirements so as we set to trains running train a lease first but it is an all stations train and it departed the outermost station at 6 AM it takes 20 minutes to reach the fifth station along the line train B is an express train it to pass the outermost station 10 minutes after the first train does but because of the travelling express it only takes 10 minutes to reach that fifth station good enough to stop and suddenly train B crashes in the back train a what's yeah totally not cool man passengers are gonna be extra pesky so are and hopefully not dead that in order to run express trains and dual track routs your only option is to clear the lane clear the lane clear the lane are medically the line clear the lane was a song he sang clear the lane was that arm rage against the machine because of we had some account I was a real anyway your authorial Goth rails again about an episode about trains are typical of me are so the thing is you could jump between the inbound and outbound is that essentially could dodge the all stations trains heading the other direct heart heading the same direction and dodge the trains heading in the other direction but if there is any congestion anywhere on the outbound leg you're screwed so you know what's says a networks grow in the demand for express trains increases you have no option but to add yet another train line that specifically intended for express trains only are some people call a bypass doesn't have a train platform sometimes they do a train platform sometimes they just go and bypass the entire train station so if you're on the aisle on the express line then you never stop at that station ever a matter what and how are irrespective of that in that situation we now have three tracks one inbound one outbound and one for express because you express trains typically follow based on the time of day is of the morning rush you have express running in an evening rush you express running outbound then I'll often run that third train line as a tidal flow system that is to say we know the direction that you have expresses changes based on AM or PM so are that's an interesting way of managing a travel corridor and still getting most of the benefits but the final expansion of your train lines comes when you start running express trains in both directions at the same time as all stations trains in both directions at the same time and that inevitably leaves you with one conclusion you need 1/4 train line to cover that circumstance and that's how you end up with a four train line configuration making sense so far cool so star versus loop is another one that made me think a lot over the years so there is a conundrum faced by cities everywhere in the world because there's always a central focal point where it all started and it's sometimes referred to as the CBD the central business district or more simply downtown in or how more recently is like 800 cash that's a hell of a deal if you know that song no Everett and yes it was a what's your budget anyway this leads to the urban sprawl and lots of jobs and I'm not gonna take up wrapping I swear I will not at least not in this podcast located in the city centre and meeting all the trains lead to the city just like all roads lead to Rome all of our train lines leading to the city centre because that's where you want to go your go downtown. There this causes network design to resemble a star pattern course you may have to use your imagination because you're sitting looks a bit like a ninja start to but again use imagination arm and is potentially some kind of psychedelic compound but it looks a bit like that so arm actually know kids don't you suck my compounds are in Brisbane though for example every single train in the entire network must travel through four stations Roma Street station central station fortitude Valley station which when I was of course younger was referred to as Brunswick Street why they have changed for Chevalier I don't know anyway and then finally no one else station there are no ifs no buts no alternatives you have to go through those four stations except there is one bypass line just one and that they call the exhibition loop but it causes the train to turn around the wrong direction to Roma Street so becoming South there is no way to get the other stations unless you swing around heading north and go through arm the wrong way around while the wrong way round physically but back to front in terms of sequence and they have and is only one lines a dozen workouts are good so if there's a problem at any of those four stations I just mentioned the ripple effect is enormous the entire network grinds to a halt and believe me it really does it totally does it's just unbelievably bad site some bright person many many years ago can cause Brisbane's architecture is not unique it's very common account with this idea of a ring or a loop and inroad parlance we would call a ring road about freeway parts I guess you'd say or in railway powers we called a rail loop rail loop ring road same idea so the idea is that not everyone wants to travel into the city is in the city isn't their final destination so let's say maybe 80% Adonai pick a number varies from city to city but the vast majority do what other people don't people are forced to travel through the city and out the other side again to get their final destination what if we designed a loop that allow people to skirt around the edges and bypass the inner city completely is even more justifiable if you're in a bigger city like Sydney when he got several distributed non-city city centres like Parramatta Liverpool Campbelltown that sort of thing and of course I do I would if I was more familiar with the open mike Manhattan or something like a proper give better examples from North American perspective but alas it doesn't literally have to be a single train that goes round and round and round round and then the sleeper doesn't have to be it just means that you could take one more trains between two different stations and never go near the city centre which is the whole point and that takes load off of that city centre right now most frustratingly Brisbane does not have a loop shame on you Brisbane fine sorry.I know I'm sorry to have to move or stop taking the train car the seller option sprawl versus speed so the other thing is from the ring relates more to how the design philosophy the train tracks are shifted from the old days as then as now so back and that the bad old days if there was a house or farm or a creek or fjord or some other, natural barrier of some kind you know some immovable object were difficult to move objects the train line would just go around it and if the train trip took an extra five minutes then I well do bad so sad that our passengers writer to train in trains call JuJu target jogger but that's the way is to be right it's like people were into church overture JuJu junk army when they witness much of a hurry inner but as a result the trains tended to get a reputation for being so slow means of transportation because you aeroplanes and no freeways and so on but when I happened that then put pressure back on the trains like a couple what if we didn't have to go around the farm we didn't have to go round the mountain and that resurgence that you could have an incredibly fast train that started to have as lead I think the pinnacle that was the TGV in France and there is one thing about high-speed trains that a lot of people don't understand and it's all well and good to have common bogies connecting carriages having streamlined low drag coefficient pointy nose train things the punch holes in the air blah blah but you know what it's useless completely useless without a straight flat smooth train line if you try and make a train going 500 km an hour go around a right-hand bend that's you got a 60 cane hour speed limit well you fly off those tracks pretty convincingly so you have to have a straight level flat track that is smooth as silk in order to go those sorts of crazy speakers in a train so the new condition that railway line engineers now have to optimise just got change the goalposts just change no longer is about getting people between point A and point B the minimal cost now everyone looks at time because time is money we get them between those two places as quickly as possible more importantly quicker than driving quicker than taking the bus mind you if you're taking a personal Learjet into work good for you or a helicopter again good for you that's nice so you know for normal people the train has to be quicker now but that you have a quick and alternative means of transportation otherwise there is no incentive to use it other than cost and even then some loss of cheaper so train line as an example near my place between Caboolture and beer bar that was upgraded about six years ago from being single track cannot believe as a single track for the longest time it was only the busiest single train line in Australia and had been for a long long time I finally upgraded to a three line system they built new bridges they bought a huge strip of a strawberry farm because my where I live I got a macadamia farm down the road of got strawberry farms pineapple farms really is a nice area for that sort of stuff that you kids love it anyway arm but what I did is I just punched a massive hole through a hill just to make the train line straight flat and increase the top speed 240 K is now Anak up to minutes of the travelling time just between our boardroom and limber and then from a limited beer Barham are again another two minutes despite but by straightening the line in because the original line and a series of tight sweeping curves and avoided the hills and the houses in the farms but that was then and this is now and now we feel the need the need for speed they said they said more disturbing when I said out loud then was in my head sorry and I air it was I think it's about another matter networks and stuff they aren't so signalling what about them signalling our Vic sure that was upon which is versus a stopgap start businesses think that that that's the stoppers signal has okay fine you nailed it with the going off the rails before it's okay so I should go it's late for me okay signalling sofa trains again does reiterate takes a long time stop you can't always see what's coming and you're travelling fast in many cases so the methods that we use the cars trams in light rail just won't work safely enough so trains heavy heavy rail trains to remount now from our trains today generally employ what is referred to as an occupancy or block based system and will use different forms of signalling the most common acronym that I've seen used is MAS which is multiple aspect signalling or multi-aspect signalling mass so train traffic lights they look like normal road traffic lights in some cases our son is referred to as the train signals or traffic signals I guess but they operate on a can fundamentally different philosophy to traffic lights do for cars on the road to traffic lights on roads that based on the idea of flow control whereas signals and train networks are based on occupancy control and understand why the different is the problem with everything I get estate this upfront for a go any further everything from here on there is a lot of variation between different states in the same country between different countries around the world it is absolutely impossible for me to drive to describe them all and to be complete about it in fact some things are about to say you may say while that's different for our train network in our country and you damn right probably years but I guess my problem is that I've done a lot of research and there's been a different countries not paid attention to the different signalling methods are used and I'm gonna try and keep this as generic as I can up was the same time covering as many of the most common options as possible so with that said ski gun essentially signalling to go for the two broad types your mechanical signalling and got coloured signalling and of these they broadly indicate two classes of of indications you got point positions as in switch track positions and block occupancy of the trains intended path and intended path as important as will get to later so mechanical singles first arm semaphore are like maybe semaphore with the flags we gather at the flags that set man but mechanical flags like I they vary from country to country but they usually like a combination of white red or black because that's high contrast in the usually rectangular alarms and I have a pivot point at the poll when I came to the poll they set high on a pole beside the railway line usually adjacent to the points or just before or after a station where there is a logical break in the blocks on workers operate to track a bit of a series of blocks are the blocks could be you are like a mile too long and dark and that's what he thinks it now before electric and remote points which is everything they were physically mechanically coupled by linkages like a mechanical solid steel bar linkage to the point mechanism so when you would lift and turn the point control arm the angle of the semaphore and the mechanical signal would change now the standards vary around the world obviously but directly out horizontally almost always means stop are directly upwards and always used where it is used at all almost always means proceed if it is tilted up or down at an angle it is usually means proceed with caution or simply just proceed so colour signals for block opt occupancy unfortunately vary a lot but where you see colour signals red is almost always used to mean stop as in there is a train occupying the next section of railway track so it is not safe to proceed after that there is pretty much nothing in common so will do is just talk about the end that the mass multi-aspect signalling used locally here in Brisbane freeze and as an example of a one way of doing so predominately used for aspect signals one red one green and two yellow set out indicator lights for the traffic light so looks like a drug lighten some idiot put a second a second yellow light a second amber light on their lips I have a spare yellow light was put on here so the idea is each of the lights indicates which block or series of blocks is occupied so red means that the next block is occupied do not enter the train currently on that block so the next rank of the light cyclops car going in for because as a train on the block again stopping now are one yellow light means that the next block is clear but the block immediately after that is occupied by train so you could go but go with caution because if you go too fast and you get the next block it is gonna hit a red light probably two yellows means that the next two blocks are clear but the block immediately after those two is occupied by train and then finally green means the next three blocks consecutively are clear of trains so that is an example of how they've done it here in Brisbane and darts storm license well for Brisbane but hate the rails is different so it is no real standard because who needs a standard right you know praise the railways in support positions they usually little clusters of lights out the budget also mechanical indicators so mechanical indicators usually will be like a black circle with a white ad bar usually are as a diagonal is either while I guess it's either level or at an angle and the angle could indicate which side the point is connected are pointing downwards arm may indicate that the point is our switch to the right arm angled downwards to the left might say the points which left it depends on the position of the signal the position of the points and a country of the state you're in but anyway are using lifestyle have usually like an inverted T sub you like gum for our lights so be three and a role in the bottom with one above the middle light forming an inverted T shape our backs is quite common and which lights are on sale be like the two centre lights always beyond and the delight on the left or the right will indicate the point direction either to the right of the left arm at some systems actually use are a series of three or four smaller lights and make Howard an upward angle directly above the yard the main traffic lights and are some people refer that as a feather listing Queensland a call in feathers and battled essentially then informs you about the other point position it also informs you about the condition of the lights the conditional like that so you got a red light and the points are switched straight ahead it means that the block directly in front of you straightahead the points is occupied so don't proceed but if the feather is lit and the feather is off to the right it's telling you your points are now pointing to the right and that could be green because it means that if the train goes the points to the right it's in a different track and that track is clear for three blocks ahead of you so the light socket yes the lights indicate the path the trains about take is clear anyway so that's that's just the nurses are a lot more complicated than a realised she had a high note in the worst part is that there is no standard for all this stuff these go down track yet I get on set is the problem that now people know what in the priori know that I'm a bit different that's okay I sighted a trainer in and I can't get to where I want to be a city and I think about why am I stuck here and I somehow do when I'm looking at the train and the lights not exactly thinking 20 years ago I'm still not on the train watching the lights in my choir therefore lights here and so I talked a few people learn a little bit of stuff there all those notes that I got put together is five pages of notes that went into this episode most that I wrote from memory because I been on trains for so long think about for so long I find it fascinating the way the trains of evolved the way the train networks involve the signalling methods that they use because you flow control at a traffic light it's about timing yes so is the cars go forward you have a predominant flow direction and you'll run the lights on the timer and the timer says you can have two minutes of forward flow on your traffic once certificates are up go read that's it then give the other direction ago that's flow based signalling you get intelligent traffic lights to talk to each other and they also say well give me an extra 30 seconds to clear this bank of traffic in a survey might dynamically extend the timer and then you have other ones that operate in after hours like alternating trigger mode so your alternate between traffic moving in one direction and traffic coming from a side street so your plot the lights on the side street the predominant flow of traffic will continue indefinitely until it is interrupted by someone pulling in a side street yes that sort of signalling is a good is completely different to an occupancy based system which is what trains have to do the heavy trains have to do so critical a lot more to it than I realised year for all those people out there that is gonna train gave may be in smile and a happy arm there is a party to, as some envious because I can't do that that's okay arm yet any other thoughts or comments you want to make as I'm on the end of my notes and I are I think that's I could go on a lot more about trains and is arm like I doubt I'd start a memoir like rolling stock now and you know I guess but I know I don't find that quite as interesting and when I when I finish my degree I thought about going with Queensland Rail but it was a brief thought and I know people that are still there are mine I'm I'm coming up to 2 decades now of engineering arm tabulate this year I will be in a world done 20 years of engineering and are its it's funny because you see people on LinkedIn this like come coming up to my arm you 20th working anniversary Queensland Rail and Mike Hall my God really they left Jenny then went to work for QR and they never left and I get that I'd I just get stir crazy a go and try different company are my longest into the company was 6 1/2 years and arm now it I decide get itchy Fiona honour I was listening you to think differently a II just I need to learn more I can't just be idle and continue to grind to the same old stuff as I go we doing today are we gonna arm have a look at the same train line with looked at the last 20 years and we opens more ballast might be like kill me now is given to a building they'll can mobilise my command to recommitment the mag 11 like nope no maglev are you get out and belong here your high-speed TGV nope demonstrate that nope can be tweak nope if not more about this cigarette mounts. John city or you can follow pragmatic show are to specifically see show announcements and other related stuff I remember the pragmatic is now part of the engineer network and it also has an account on Twitter at engineered_net at all/announcement about the network and all the show so you can check that out an if you'd like people are really loving causality and new trim as well so if you like pragmatic be sure to check those out if you like to get in touch with Vic was the best way for people to get they can find me on Twitter advocate someone fantastic and are if you're enjoying pragmatic and will support the show the best way is by becoming a patron by patriarch it's at Patriot GG all one word and that if you'd like to contribute something anything at all it's all greatly appreciated is also the person there if you'd like to access the raw show notes and show backers can have a name thank you if they want at the end of each episode so check it out as I said it all helps and all very much appreciated arm thank you everyone for listening once again and as always thanks for you that's good water because of our coffee now 11:10 that would be a bad play PB up on this is all night this is me up all night talking trains right as did a metal symbol with my fingers there for that be near the double point yes it would I'm on think I'm channelling K Craig Federici just now anyway out either Olivia that image in my head when he wanders onto the stage arm is W WDC says and we gonna call it metal it is the fear as there are other friend was a good trade Federico will forever be cool in my heart because of that one moment I care about engagement is damn hair that one moment is or need´┐Ż
Duration 49 minutes and 7 seconds Direct Download

Show Notes

Miscellaneous Links:

Episode Gold Producer: 'r'.
Episode Silver Producer: Chris Stone.
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Vic Hudson

Vic Hudson

Vic is the host of the App Story Podcast and is the developer behind Money Pilot for iOS.

John Chidgey

John Chidgey

John is an Electrical, Instrumentation and Control Systems Engineer, software developer, podcaster, vocal actor and runs TechDistortion and the Engineered Network. John is a Chartered Professional Engineer in both Electrical Engineering and Information, Telecommunications and Electronics Engineering (ITEE) and a semi-regular conference speaker.

John has produced and appeared on many podcasts including Pragmatic and Causality and is available for hire for Vocal Acting or advertising. He has experience and interest in HMI Design, Alarm Management, Cyber-security and Root Cause Analysis.

You can find him on the Fediverse and on Twitter.