Driving with Cab Signalling

I had a go on a driving simulator for a metro line yesterday. The line concerned has cab signalling, with no line-side signals or speed signs. Your maximum permitted speed is shown on the speedo, and regularly changes. In order to keep within acceptable speeds, I found that I was having to watch the speedo almost constantly, almost ignoring the view out the "window". Is this normal with cab signalling?

Totally normal. Even to the point where you can 'drive' with the front blind down. Its a weird experience but totally acceptable. I've seen it demonstrated in a Eurostar run and experienced it first hand on HS1

To be honest unless there is something wrong it’s little different to normal driving. I don’t look at the speedometer anymore than I would do when driving under line side signals. In fact I’m looking out the window a bit more to adjust power for the severe gradient changes on HS1.

It's surprising that there isn't a headup display

Are there any audio notifications?

The ones I'm familiar with from the USA, who have been into cab signals quite extensively since the 1930s, both subway and main line, do a "Bong" when they change. So you don't need to be transfixed on the display.

mark-h said:

Are there any audio notifications?

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On all the LU systems there are audible tones associated with various events, in particular changes in speed. In theory it should be possible to drive looking out the window, and only looking at the speedometer when a tone is heard. Reality is rather different however...

A lot depends on how close to the target speed one wishes to drive. Again referring to the LU systems it's quite possible to drive bang on, in terms of both speed and brake rate, albeit requiring a fair amount of concentration and on the TBTC system in particular being subjected to numerous "overspeed immiment" warnings. However it is rather satisfying to be able to match, or even very slightly improve upon, ATO performance - whilst at the same time driving the train "properly" (e.g. paying attention to such little things as throwing the brakes fully off at the last second before stopping to achieve a seamless stop)!

The Central Line system achieves a rather more satisfactory balance between looking out the window and looking at the speedometer, as the stopping location will always be a fixed trackside object, in some cases a proper signal. The only snag is some of the signals and block marker boards are appallingly sited for sighting purposes!

Once again referring to the LU systems, perhaps the biggest issue with in-cab systems is that they're subject to quite a lot of software issues, where software design errors have found their way into the finished product but haven't been corrected for whatever reason. The Thales systems are notorious for this, although even the mature Central Line system still has things which aren't supposed to happen, and are just put down to "that's how it is". The Northern has so many issues it does make driving an "interesting" experience, although like with any signalling the driver will eventually get used to it and drive accordingly - just like with signals where drivers get used to how they work, although a signal flapping to red for a second would raise eyebrows, whereas Thales just dismiss it as a "blip"!

Belperpete said:

I had a go on a driving simulator for a metro line yesterday. The line concerned has cab signalling, with no line-side signals or speed signs. Your maximum permitted speed is shown on the speedo, and regularly changes. In order to keep within acceptable speeds, I found that I was having to watch the speedo almost constantly, almost ignoring the view out the "window". Is this normal with cab signalling?

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I guess in some ways this is similar to normal signalling, a driver spends most of his/her time looking out of the window to observe the signals and drive to them. Signalling is how trains are driven irrespective of how they are observed. The only times I can think it absolutely necessary to keep a lookout is at level crossings, coming into platforms and in and around yards/depots. I’m sure another driver can think of other many occasions to add on to that but in cab signalling or lineside signalling is kind of the same principle really, just with lineside I guess seems more natural and you get the best of both worlds in regards to being attentive to the line when needs be

reading this thread is quite funny
you drive a sub or EPB you have no speedo and judgment would be fairly close maybe 10% out no track side speed markers but later speed cutouts
at night the route was in the head with 100% route knowlege from memory headcode was for people on the track to see the train coming providing with zero help to the driver
driving was fully by knowing exactly where your going with bridges gradients track sounds local landmarks all being cues to what actions you need to take
indeed whilst driving a crompton on a van train from tonbridge to redhill about 25-30 years ago i said to my freind i would cover the speedo on leaving tonbridge and ease back at 60 and approaching edenbridge at precisely 59mph eased off with no effort or input just by natural feel

A few years back I went through the channel tunnel in the cab of a freight shuttle and saw the tvm430 signalling first hand . From what I can remember speed changes were preceded by a bleep then display started flashing and you couldn't see anything out of the windscreen in parts .

bramling said:

Once again referring to the LU systems, perhaps the biggest issue with in-cab systems is that they're subject to quite a lot of software issues, where software design errors have found their way into the finished product but haven't been corrected for whatever reason.

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The fundamental issue here is that software 'engineers' do not work to anything like the standards of professional practice expected of professional engineers in other areas.

RLBH said:

The fundamental issue here is that software 'engineers' do not work to anything like the standards of professional practice expected of professional engineers in other areas.

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No. The issue there is management. Management always think vast and complex software systems are easy and expect too much to be delivered too quickly. Usually time or cost pressures add into this.

Software Engineers are only to blame if they didn't speak up and bring down expectations.

I've driven a tube train with in-cab signalling and whilst it's a little disconcerting at first, within a few trips you adjust quite easily to it and you can drive it quite accurately with the blinds down (not that this should be encouraged!). You start by driving nearish to the target speed but you'll soon be driving at the required speed. You're given notice of changes of speed and you have a 'distance to go' appear on the TOD to let you know how far until the next event whether that's a station stop, a train in front or a speed restriction, etc.

At the beginning you do tend to concentrate on the TOD rather than what's going on outside but after a while you just glance at it when you hear an accompanying audio tone and react accordingly. The braking profile is not that severe either so you have plenty of wiggle room should you over/under brake.

CLH said:

No. The issue there is management. Management always think vast and complex software systems are easy and expect too much to be delivered too quickly. Usually time or cost pressures add into this.

Software Engineers are only to blame if they didn't speak up and bring down expectations.

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The classic problem with software managers is that they often fail to understand the difference between something being conceptually simple and easy to implement. This then means they fail to realise how long something should take to implement properly.

Our system has a “slippery” setting. Knowing first hand how varied a slippery rail actually is, I wonder how much “wiggle” room you actually get before the next stop point.

Oh, I said “our” system, I’m only trained on it to level zero, which means I’ve got permission to log on and see my speed, that’s it. Level 2 is where you actually use the thing.

sw1ller said:

Our system has a “slippery” setting. Knowing first hand how varied a slippery rail actually is, I wonder how much “wiggle” room you actually get before the next stop point.

Oh, I said “our” system, I’m only trained on it to level zero, which means I’ve got permission to log on and see my speed, that’s it. Level 2 is where you actually use the thing.

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Your mob still not rolled out DAS fully then? The Cardiff guys were testing it when I was there 2 years ago, with a view to full use by now!!!

Level two is only on the Cambrian line. Everywhere else is lineside signalling. Network rail have said that if the system is in working order on the train, then it must be used. Obviously it’s a long way off around New Street so there has to be a level zero for the rest of us to use.

sw1ller said:

Level two is only on the Cambrian line. Everywhere else is lineside signalling. Network rail have said that if the system is in working order on the train, then it must be used. Obviously it’s a long way off around New Street so there has to be a level zero for the rest of us to use.

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Apologies, I've got confused between DAS and ETCS - I forgot the 158s had cab signalling

tiptoptaff said:

Apologies, I've got confused between DAS and ETCS - I forgot the 158s had cab signalling

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You know what, I didn’t even click when you said DAS..... yeah that’s fully rolled out, I tend not to bother with it though. And we don’t called it ECTS, it’s ERTMS in our neck of the woods. Haha

sw1ller said:

You know what, I didn’t even click when you said DAS..... yeah that’s fully rolled out, I tend not to bother with it though. And we don’t called it ECTS, it’s ERTMS in our neck of the woods. Haha

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We used to just let the Machy Private Railway get on with it...! Never dealt with it much

CLH said:

No. The issue there is management. Management always think vast and complex software systems are easy and expect too much to be delivered too quickly. Usually time or cost pressures add into this.

Software Engineers are only to blame if they didn't speak up and bring down expectations.

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Management are certainly to blame for accepting rubbish, however the attitude and competence of Thales leaves a lot to be desired.

mark-h said:

Are there any audio notifications?

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There were, if you failed to keep within the acceptable speed range.
There was no distance-to-go type display, or warning of impending speed restriction ahead, just a speed band that would steadily rise when accelerating away from a stop, and likewise steadily drop when approaching a restriction or stop. I suppose with experience you would learn where the speed restrictions ahead are, and if the permitted speed started dropping unexpectedly it would be due to an obstruction ahead (train ahead, route not set through junction, etc), so you would just start service braking until the permitted speed started rising. However, it was a bit like one of those games where you have to thread the loop along the twisty wire - take your eyes off it and the buzzer soon rings.