Should Train Drivers sit a basic physics examination as part of their training?

[GC class B1]

The train ran incorrectly as class 5 empty coaching stock. Sorry I didn’t explain that. It should not have run as class 5 as it wasn’t braked to figure 2 of GM/RT2045 issue 4. Also the driver had selected freight timing so presumably he treated it as a freight train.

 

[niggill617@gma]

@niggill617@gma hasn't specified what a 'class 5' is and I don't know what RAIB report this is referring to so I couldn't check.

Under RSSB Classification of Freight Trains Link here : https://www.rssb.co.uk/standards-catalogue/CatalogueItem/GORT3056-A-Iss-2



Only 3, 4, 6, 7, and 0 are displayed in the table.

Checking the Wiki here : https://en.wikipedia.org/wiki/Train_reporting_number



but could also be



So yeah, kinda wanted more information.

Read the report as highlighted last paragraph.

 

[niggill617@gma]

What if its just a DSD test ?



This is no longer part of the psychometric testing requirements. Maybe an A-Level in Physics and Maths should be required. I know that Math GCSE is slowly becoming a requirement but maybe Physics should be added too ?



Dunno. I just do it because I'm told to. Normally I'd drinking a cuppa during the FPBT (Full Personal Brake Test) or a minimum DSD (Drivers Safety Device) test that i don't notice the full braking capability of the unit. Maybe this could also be checked with the RAIB to see why this is done and what it is supposed to achieve.




F=MA (force = Mass x Acceleration)




Because it was ECS ?

@niggill617@gma , you may be detecting some scepticism in the replies you are getting. And I note that many of the railway professionals who are on this forum are not engaging with this discussion.

I'm not in the profession, but I am a professional mathematician, and am qualified to read and understand the legislation you are referring to.

I think you are referring to Schedule 4 of the Train Driving Licenses and Certificate Regulations of 2010, which state that "Drivers must be able to check and calculate, before departure, that the train's braking power corresponds to the braking power required for the line, as specified in the vehicle documents." I think the key phrase here is 'before departure'. It means that this is not a calculation based on empirical evidence, but based on the information provided. On that basis, this must therefore be referring to a very simple arithmetical calculation, not the kind of physics based calculations you are talking about.

While I understand why it might be attractive to think that drivers should be able to hold mathematical models in their head that are able to account for a large number of variables, it's actually not a good idea. Such a calculation is cognitively difficult - even for experienced mathematicians. And any potential benefit will be more than outweighed by the risk of distraction.

The law reflects this - there is no requirement for calculations to be made 'on the fly'. And I cannot see any possibility that a responsible group of lawmakers would think that this would be a good idea.

It would seem to me that the regulations strike a good balance - yes drivers should take time to consider whether the known capabilities of the train are suitable for the route to be taken before starting off. And with a suitable amount of experience of driving, they should be able to detect if something is not working as expected, without having to justify it with a needlessly complicated calculation.

I don't see any possibility of the change you are advocating ever happening.

Note highlights on attachment.

Just what do driving instructors teach during exposure training (sitting with Nellie)? Brake at the white house no brake at the pink house says the next, "oh my wheels picked up" Polarised braking mentality, often for the gain of very little, for the risk of very much.

Teach some theory and have parameters.

 

[WideRanger]

Refer to Appendix A curve A1, compare that to fig 7 of the report, 1 in 508 falling with 15 seconds freewheel. What is your conclusion?

My conclusion is that the professional investigators will be able to come to conclusions based on far more data than is available to you or me. I don't think it is helpful to anyone for outsiders to second guess how they are doing a very challenging role.

On the answer to the original question, do I think train drivers should sit a basic physics exam as part of their training: I haven't seen anything in this thread to suggest understanding of physics by train drivers is generally deficient given the requirements of the role.

On whether train drivers should be able to do an accurate (or even rough) calculation of coefficients of friction or potential breaking power from first principles and based on real-time empirical evidence: absolutely not. That would not be a sensible use of the science, and would almost certainly lead to less safe outcomes.

While I applaud your keenness to engage in a subject that you feel passionately about, the effort you are putting into this is unlikely to have any real-world outcomes. So, if you find it satisfying, do enjoy the mental challenge of it. But equally, it would seem likely that the relevant authorities are going to continue to not engaging with you and the points that you are making.

 

[GC class B1]

My conclusion is that the professional investigators will be able to come to conclusions based on far more data than is available to you or me. I don't think it is helpful to anyone for outsiders to second guess how they are doing a very challenging role.

On the answer to the original question, do I think train drivers should sit a basic physics exam as part of their training: I haven't seen anything in this thread to suggest understanding of physics by train drivers is generally deficient given the requirements of the role.

On whether train drivers should be able to do an accurate (or even rough) calculation of coefficients of friction or potential breaking power from first principles and based on real-time empirical evidence: absolutely not. That would not be a sensible use of the science, and would almost certainly lead to less safe outcomes.

While I applaud your keenness to engage in a subject that you feel passionately about, the effort you are putting into this is unlikely to have any real-world outcomes. So, if you find it satisfying, do enjoy the mental challenge of it. But equally, it would seem likely that the relevant authorities are going to continue to not engaging with you and the points that you are making.

I think you have misunderstood the point of drivers understanding the principles of train deceleration. For the incident mentioned, the driver was incorrectly told the braking effort for the train was sufficient for a maximum speed of 75MPH. The deceleration achieved was far less than would be required for this maximum speed (about half) and this was the cause of the incident. I am sure that most drivers have an understanding of train braking principles, however there are occasions were the train braking capability is not as designed. The suggestion is that, if during training, all drivers were the provided with the tools to better enable them to identify that the braking performance of their train was less than required to enable the train to stop within the signalling distances at the maximum speed, then incidents of this nature would be avoided.
As I pointed out in my earlier post the calculations are simple and don’t require knowledge of the coefficients of friction or calculations from first principles.
I have also noted that there are a number of anomalies in this particular report. Although I agree with the report findings that the maximum speed of the train advised to the driver was was higher than it should have been, there are inconsistencies in the data presented and the subsequent analysis. As an example the stopping distances at half brake are much less than would be expected by using the details in the report and calculating the deceleration rate at Full Service from the recorded stopping distances. I have determined the deceleration rate that should be achieved at half brake using the details provided in the report. From this value i have calculated that with the drivers brake valve moved to a position half way between Running and Full Service position the stopping distance should be around 2800 metres. The post incident test stopping distances with what is stated as half brake were around 2300 metres.
I have also calculated that in order to recreate the circumstances of the incident I.e. passing the red signal by 200 metres, with a Full Service brake application, as determined by the post incident stopping distance tests, the train would have passed the red signal at about 28MPH and not 20MPH as suggested in the findings.
The report also concludes from the post incident testing that brake performance of the two locomotives was satisfactory. Using the TOPS value of 60 Tonnes for GB brake force the retardation rate for each of the class 57 locomotives should be around 8% g when braking from 75MPH. From the stopping distance testing carried out, I have calculated that the average retardation for the two locomotives was just over 6%g. If both the locomotives had been braking to the expected retardation rate of 8%g, the deceleration rate for the train including the unbraked EMU would then have been around 5%. This would result in a stopping distance at Full Service/Emergency of around 1400 metres. The stopping distance at half brake would also have been shorter. The conclusion can therefore be drawn that if the brake performance of both class 57 locomotives had been within design tolerances, the SPAD would probably not have occurred even though the train was exceeding the maximum permitted speed.

 

[niggill617@gma]

My conclusion is that the professional investigators will be able to come to conclusions based on far more data than is available to you or me. I don't think it is helpful to anyone for outsiders to second guess how they are doing a very challenging role.

On the answer to the original question, do I think train drivers should sit a basic physics exam as part of their training: I haven't seen anything in this thread to suggest understanding of physics by train drivers is generally deficient given the requirements of the role.

On whether train drivers should be able to do an accurate (or even rough) calculation of coefficients of friction or potential breaking power from first principles and based on real-time empirical evidence: absolutely not. That would not be a sensible use of the science, and would almost certainly lead to less safe outcomes.

While I applaud your keenness to engage in a subject that you feel passionately about, the effort you are putting into this is unlikely to have any real-world outcomes. So, if you find it satisfying, do enjoy the mental challenge of it. But equally, it would seem likely that the relevant authorities are going to continue to not engaging with you and the points that you are making.

RAIB have been critiqued for taking too long to produce reports. One satirical group refer to them as Read About It Belatedly. (deathbyhealthandsafety.co.uk)

No second guess, 20 mph uniform deceleration for 200 m = 0.199 m/s/s.

Edinburgh is not the only example of poor brakes and near disasters. ( moderators have a copy of my letter to the HSE).

If we have a train crash relating to a lack of kinematic understanding, my posts and little campaign may well flush out some accountability. Polarised braking mentality or lack of supervision; Croydon Incident. RAIB report 18/2017 paragraph 81 and 128.

 

[Annetts key]

My conclusion is that the professional investigators will be able to come to conclusions based on far more data than is available to you or me. I don't think it is helpful to anyone for outsiders to second guess how they are doing a very challenging role.

Signalling engineering staff often debate and discuss investigations involving allegations against signalling equipment when the RAIB investigate. As said above, they do take a long time even when the event appears simple or straightforward. Some of their investigations take years…

Compare that to a typical internal railway investigation into a serious allegation that signalling equipment may have functioned in an unsafe way (wrong side failure). These typically take between 12 hours and four days. Not over a year.

On whether train drivers should be able to do an accurate (or even rough) calculation of coefficients of friction or potential breaking power from first principles and based on real-time empirical evidence: absolutely not. That would not be a sensible use of the science, and would almost certainly lead to less safe outcomes.

I don’t think anyone is expecting a driver to do any complex calculations while driving a train. However, a driver should understand basic physics in relation to motion, friction, potential energy, kinetic energy, etc, so that he or she can compare the actual performance of the trains braking system to what they expect.

More than once drivers of high speed trains (class 43 HST power cars and mark 3 coaches) have driven in service passenger trains where part of the braking system has not been operating correctly. And by driven, I mean to and from London Paddington in passenger service at normal line speeds including 125MPH.

In hindsight, they probably realise that the trains should have been taken out of service as soon as the driver noticed that the braking was no as expected.

But to their credit, these drivers adapted their driving to cope with less effective brakes.

If a train driver discovers that the braking system of a train he/she is driving is less effective than they expect, they should adapt there driving to cope with this. And if it is the train that is at fault, it should be taken out of service.

Signalling systems and the spacing of signals (to each other and to points, junctions, level crossings) all depend on trains meeting their braking specifications.

If a driver loses control of a train, there is a significant likelihood of an overrun (SPAD), derailment or crash.

 

[Cowley]

I don’t think anyone is expecting a driver to do any complex calculations while driving a train. However, a driver should understand basic physics in relation to motion, friction, potential energy, kinetic energy, etc, so that he or she can compare the actual performance of the trains braking system to what they expect.

We feel that everyone has probably had their say on this subject now and this is probably a good place to leave it.

Thanks for your contributions everyone, it’s much appreciated.