Modern cabs - do they overload the driver with information?

[cjmillsnun]

If drivers feel overloaded now, just imagine when ETCS is rolled out

That may be easier as they won’t have to remember what the last signal was.

 

[Ediswan]

Whilst, thankfully, the railway is already so safe that even if a driver makes a mistake due to not fully understanding the information presented or due to distraction from "all those bleeding flashing lights and doodads!" that the chances of a serious disaster are fairly remote but I do wonder if the industry and specifically those that design the cabs and the UI of the computers that go into them are fully alive to such issues and give them the respect they deserve?

Is there any system by which those designers can get cab rides to give them a better idea of how the real world works ?

 

[aleggatta]

Have a look at a picture of a class 710 cab, it's just overload.

For a case in point of what distractions are possible, on one class of our new units some bright spark has decided to perform a software update that means that any time some passenger presses a 'call for aid' (every few minutes now on a Friday/Saturday night) the main TCMS ('driver') screen that displays the drivers power and brake position, and is safety critical, suddenly reverts to a page that only shows the PA system. The driver doesn't even operate the PA on our units, we have guards for that. This is a recent software change and would be a huge distraction at certain critical moments considering the change in screen to something useless is also accompanied by lights and a loud audible alarm - not what you want when you're a coach length from a buffer stop.

I just have one query with your initial statement. Why is the 'Driver' screen considered safety critical in showing the power and brake position? I would have thought physically having your hand on the controller would tell you where the position of the handle was, or is this a similar thing as to electrostars where they have the seemingly useless 'power usage' info available to drivers that doesn't seem to be of any real aide to driving. I'm not familiar with these units so it could well be that the speedo is on the drivers screen and I would be suitably disappointed with the designers for allowing an alarm to cover the speed indication on a unit.

 

[Llama]

As I said in an earlier reply, if the CPBCs all 'felt' the same then yes we'd be able to get used to them but they're obviously quite badly made as the levels of friction and/or sloppiness vary with every one - even in both cabs of the same unit. They are continuously variable for both power and brake and, apart from a slight click at about 10% into each arc, there's no notching, just free movement. It was also discovered early that on some of the 331s the extra 'clunk' - when you go beyond 100% service brake to the emergency brake position - the CPBCs would need superhuman strength to actually get it to go into emergency.

These things (and many more) should have been ironed out, but, politics.

 

[TheEdge]

I just have one query with your initial statement. Why is the 'Driver' screen considered safety critical in showing the power and brake position? I would have thought physically having your hand on the controller would tell you where the position of the handle was, or is this a similar thing as to electrostars where they have the seemingly useless 'power usage' info available to drivers that doesn't seem to be of any real aide to driving. I'm not familiar with these units so it could well be that the speedo is on the drivers screen and I would be suitably disappointed with the designers for allowing an alarm to cover the speed indication on a unit.

Speaking with experience of the 755s that readout of what is actually happening behind the PBC is important on this generation of units, especially with modern WSP. You can put the handle in the same position on the same unit in two different locations and the actual brake performance can be different. The FLIRTs allow the WSP to pick and choose on the fly between using the dynamic or pneumatic brakes, the readout tells you which as 30% application on dynamic brake is noticeably gentler than a third on pneumatic. Perhaps the WSP has detected a bit of slide but is dealing it by using a slightly lighter or heavier amount of brake. The readout tells us this, not the PBC position. Same taking power, same position can result in different power delivery depending on multiple factors.

It worth pointing out that I can tell all of that by feel but not as quick as I can tell from the TCMS, especially slip and slide at this time of year.

 

[Llama]

That's very much how 195s are - the dynamic brake is only maybe half as effective as the friction brake is - what you get when you put the brake in seems to depend on tea leaves. Plus trying to brake on 50% (or fewer if a transmission is playing up!) of axles adds an interesting dynamic in low adhesion. As such I agree that you need to know the percentage of brake force taken as say 30% friction brake is broadly similar to say 60% on the dynamic.

 

[20atthemagnet]

Have a look at a picture of a class 710 cab, it's just overload.

For a case in point of what distractions are possible, on one class of our new units some bright spark has decided to perform a software update that means that any time some passenger presses a 'call for aid' (every few minutes now on a Friday/Saturday night) the main TCMS ('driver') screen that displays the drivers power and brake position, and is safety critical, suddenly reverts to a page that only shows the PA system. The driver doesn't even operate the PA on our units, we have guards for that. This is a recent software change and would be a huge distraction at certain critical moments considering the change in screen to something useless is also accompanied by lights and a loud audible alarm - not what you want when you're a coach length from a buffer stop.

As someone who drives them not really sure where this "Overload" stems from? Its one of the cleanest designs of cab of the half dozen units I've driven in my railway career spanning 3 generations of train. A TCMs, a DMI with digital speedo and integrated TPWS, and two DOO monitors (with touch allowing you to zoom on individual images) with a few knobs/buttons scattered around (somewhat intuitively) for HVAC/lights etc. TCMs is logical, obvious and intuitive, with faults being obvious and not open to interpretation, unlike its older Electrostar brother who's TCMs wasn't awful but had no logic to its menu structure whatsoever. More importantly no requirement for you to ever leave the driving cab for faults/failures/CFAs or PEAs. Also a ton of visibility that most ironically try to get rid of by lowering the blind to almost a slither as the amount of light let in otherwise is akin to being 1000km from the sun...

710s are only fully variable for power, braking is traditionally (an somewhat unofficially) 3 step "notched" unlike 345/720s that are variable too, which is sufficient along with my bum to tell me what the train is doing. Although for a fully variable handle the CTBC angle always visible on the TCMs for me on a unit would be a must have, as you cant "feel" anything through the handle between its coast and maximum and minimum extremities. However fully agreed with the discrepancies between units with some being loose, others with a lot of friction, that annoys me to no end.

 

[ComUtoR]

I'd also add that some specific brake / power steps are required by the TMS and also required by driving policies.

Our running brake tests are 60% minimum. So having a readout is almost essential to ensure its been carried out at the right percentage.

Any of our slow speed modes need to use less than 33%

Having some kind of visual indication helps.

 

[20atthemagnet]

I'd also add that some specific brake / power steps are required by the TMS and also required by driving policies.

Our running brake tests are 60% minimum. So having a readout is almost essential to ensure its been carried out at the right percentage.

Any of our slow speed modes need to use less than 33%

Having some kind of visual indication helps.

Good point. This is exactly why 710s were notched compared to their siblings, to conform with the existing driving policy.

 

[theking]

Think some people want to hark back to the days of two leavers and a brake cylinder pressure gauge.

If you get overloaded by a class 710 cab then you really shouldn't be driving a train.

 

[TheEdge]

Think some people want to hark back to the days of two leavers and a brake cylinder pressure gauge.

If you get overloaded by a class 710 cab then you really shouldn't be driving a train.

The cab on its own perhaps but when you are approaching a red at night and someone pulls a passenger alarm and then there is an audible alarm, a visual alarm on one screen, a bright yellow or red readout on another screen, a flashing lamp on the desk and a live CCTV screen on a third suddenly it becomes very easy to forget or be distracted from the signal.

 

[Llama]

The cab on its own perhaps but when you are approaching a red at night and someone pulls a passenger alarm and then there is an audible alarm, a visual alarm on one screen, a bright yellow or red readout on another screen, a flashing lamp on the desk and a live CCTV screen on a third suddenly it becomes very easy to forget or be distracted from the signal.

Exactly this - normally there's not a great deal going on, and that includes our wonderful CAF units, but the potential for intrusive alarms at critical moments gets given little thought when these things are designed.

Decent drivers always think "what if".

 

[Skoodle]

I don't think modern cabs are overload, I'm confused by the comments about drivers relying on the screen to tell them what position the PBC is in, it's normally possible by feel and you can tell if your train is slowing down or speeding up anyway.

However the one thing I long for on Mitrac (Electrostar TMS) is dark mode!

Our iPads for DAS/TAS have dark mode, it surely wouldn't be too hard to have dark mode on the TMS?

As a result most drivers turn the screen off completely once it gets dark, so that they can actually see out the windscreen in front of them.

On the 378s we have dark mode. When selected, after the train goes above 4mph the TCMS screen turns off and dark. Is that what you mean, or have a dark mode that switches to black background and white text so you can still see the screen?

In regards to the PBC position, the newer Aventra units have a smooth PBC and Brake (345), although for ARL (710), they pushed Bombardier to make the brakes remain as brake steps but the power is "un-notched". I don't drive them myself but I can understand that it'd be harder to work out where the PBC is placed.

 

[357]

On the 378s we have dark mode. When selected, after the train goes above 4mph the TCMS screen turns off and dark. Is that what you mean, or have a dark mode that switches to black background and white text so you can still see the screen?

In regards to the PBC position, the newer Aventra units have a smooth PBC and Brake (345), although for ARL (710), they pushed Bombardier to make the brakes remain as brake steps but the power is "un-notched". I don't drive them myself but I can understand that it'd be harder to work out where the PBC is placed.

I mean more like dark mode on newer phones and laptops. All information visible but doesn't blind you. Our Electrostars also have the ability to turn off the screen in the same way.

The iPad apps already in use have it.

 

[TheEdge]

Interestingly the FLIRTs effectively only have a dark mode. Black screen, white text, dimmable at drivers will, along with the ability to turn the screens off. The only elements that are coloured are TCMS fault messages, the main alarm "button" and ASDO health indicators.

 

[Bikeman78]

Even when they were brand new every CPBC felt different. They've not got better with a couple of years of use. I assume there's meant to be a certain element of friction in the movement through the arc to power and to brake, but some are completely free of friction to the extent that if you let go of the CPBC it will spring towards the extreme or minimum of whichever direction it had been applied (so the brake can be biased to spring back to release, and the traction power can spring towards maximum - both a bit dangerous really). Some others are so stiff to move that drivers have complained of arm & shoulder pain.

This probably explains the jerky braking that I experienced on my first ride on a 195. Not been on many more but they have been okay.

 

[O L Leigh]

The cab on its own perhaps but when you are approaching a red at night and someone pulls a passenger alarm and then there is an audible alarm, a visual alarm on one screen, a bright yellow or red readout on another screen, a flashing lamp on the desk and a live CCTV screen on a third suddenly it becomes very easy to forget or be distracted from the signal.

But when that happens you just stop. It doesn’t really matter precisely where, but you get the thing stopped and then deal with the issues. The same applies in any situation where you feel overloaded.

 

[TheEdge]

But when that happens you just stop. It doesn’t really matter precisely where, but you get the thing stopped and then deal with the issues. The same applies in any situation where you feel overloaded.

Well yes in reality. I was just trying to make the point that there are perfect storms where the amount a modern cab can suddenly throw at you can become a huge distraction.

 

[Stompehh]

Airbus aircraft have a "dark cockpit" philosophy for all physical switches and indicators. This means that if everything is OK, it should not be illuminated. This can be counter-intuitive if you are not trained to operate it, as certain things are the opposite way round to normal. For example, a fuel pump switch will be illuminated when it is selected OFF, because this is an abnormal configuration. Other things which are only used in an emergency will be illuminated when ON.

It's the difference between interfaces which have to be usable by anyone without any specific training (ticket machines, passenger call for aid, fire alarms at stations) and those which are used only by trained people (cabs, cockpits, ticket office computers). The latter allow you to concatenate a lot more information and controls into a smaller space, potentially allowing safer operation with more rapid response in an emergency scenario.

NOTE: This doesn't mean these interfaces are always designed well - clearly not, from some of the examples in this thread!

A350 cockpit: https://ccntservice.airbus.com/apps...464.771988968.1634283832-903990128.1634283832

 

[spyinthesky]

Not being in the rail industry but most industries use suggestion schemes. I work on a automated explosives facility and within the space of 2 years the suggestion scheme has had over 4,000 suggestions with about 15% implementation. Although automated there is still human intervention and risk involved but anyone from the top down is allowed to stop the facility.

 

[Llama]

This probably explains the jerky braking that I experienced on my first ride on a 195. Not been on many more but they have been okay.

Probably an inexperienced driver or poor technique if it was 'jerky' - they can be very 'on/off' unless applied from the minimum setting.

Friction brake on 195s always takes over from dynamic brake when speed reduces to about 24mph, that produces a sudden grab from the brakes unless the driver reduces the brake application with good timing.