How much or how little snow is enough to require additional RBTs and other company instructions

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Socanxdis

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If it’s just a light flurry with hardly anything on the track, are you going to do what your instructions are regarding RBTs and speeds?
 
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Stigy

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If it’s just a light flurry with hardly anything on the track, are you going to do what your instructions are regarding RBTs and speeds?
Our Appendix to the Rulebook instructions are that they’re only required during snowfall or if train passage is disturbing snow. I’d say it depends how heavy the falling snow is as to whether this is necessary.

If it’s not specific, it’s as always a judgment call. Sometimes best to err on the side of caution.
 
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LCC106

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I always think what if an incident happens? They’re going to do a download so even if it’s a light flurry it’s best to do one anyway. You don’t know when that flurry’s going to have an impact either. EDIT TO ADD if it’s in your instructions and you don’t do it they’ll want to know why not.
 

Tractor37

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For non- traincrew, could you please translate?
RBT - running brake test. Additional ones are carried out during snowfall or snow being disturbed by the passage of trains. Or also during extreme cold weather after 66734 derailed due to the brake rigging freezing. These are carried out every 3 to 5 minutes and are a full service brake application with a speed reduction of at least 10mph for all brake types. Disc brakes trains also have to run 10mph below line speed down to a minimum of 50mph.
 

Stigy

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For non- traincrew, could you please translate?
Running Brake Test.

Basically to check the efficiency of the train brake. In normal conditions you’d do a test when taking over a train or upon starting its journey, for example. It should be at a speed deemed meaningful so as to be able to check how the braking performance is.
 

73001

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For non- traincrew, could you please translate?
I was about to say the same but now I think it's something like a rolling brake test to make sure the snow isn't building up on the brakes.

Thanks to those above
 

LCC106

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Always good to sound the horn to blow any build up of snow away too. 20mph speed limit for a fully defective horn on the last part of your shift can mean a VERY late finish!
 

fulmar

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Some more recent traction units have a snow brake which does away with the need for additional running brake tests during snow conditions. The driver just has to go to the relevant screen on the train management system and press a button to engage it. Once engaged there is no requirement to carry out any additional running brake tests or reduce speed with disc braked trains. If for some reason the snow brake is not working the normal instructions for snow conditions apply. The snow brake works by gently rubbing the brakes on each vehicle in turn. The effect on the train's performance is barely noticeable except perhaps when accelerating.
 

Tractor37

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Some more recent traction units have a snow brake which does away with the need for additional running brake tests during snow conditions. The driver just has to go to the relevant screen on the train management system and press a button to engage it. Once engaged there is no requirement to carry out any additional running brake tests or reduce speed with disc braked trains. If for some reason the snow brake is not working the normal instructions for snow conditions apply. The snow brake works by gently rubbing the brakes on each vehicle in turn. The effect on the train's performance is barely noticeable except perhaps when accelerating.
We have it on the 195’s and 331’s. Only used it once on the 195 - it’s like driving with a dragging brake!
 

ComUtoR

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Once engaged there is no requirement to carry out any additional running brake tests or reduce speed with disc braked trains.

Source ? Is this TOC specific ?

Cheers in advance.
 

Intermodal

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Source ? Is this TOC specific ?

Cheers in advance.
The whole point of the snow brake is that it is constantly moving the linkages to prevent freezing. If you still do RBTs whilst using the snow brake function then you may as well not bother with the snow brake.

This isn't a rulebook issue, it's TOC/traction policy. But still - why bother if you're going to do the RBTs anyway?

Or am I misunderstanding the snow brake?
 

PudseyBearHST

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The whole point of the snow brake is that it is constantly moving the linkages to prevent freezing. If you still do RBTs whilst using the snow brake function then you may as well not bother with the snow brake.

This isn't a rulebook issue, it's TOC/traction policy. But still - why bother if you're going to do the RBTs anyway?

Or am I misunderstanding the snow brake?
The secondary reason for doing regular brake tests is so the driver can ensure the brakes are working correctly and get an idea for how much braking performance is affected. The snow brake doesn’t necessarily prove that the brakes are functioning correctly. You don’t want it to be that the only time you’re testing your brakes or getting a feel for them is when you are braking for cautionary signals, station stops or speed restrictions. But as you say, it would be dependant on company and traction.
 

bengley

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The snow brake on very modern traction is indeed designed to replace the requirement to carry out brake tests in snow and run below line speed. This is the policy at Northern with their civity fleet.

It is not currently the policy at TPE but I believe it is being looked into
 

ComUtoR

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It must be TOC (or traction) specific as I can th ink of traction that have a snow brake but still require a running brake test to be done regularly.

Same here.

The whole point of the snow brake is that it is constantly moving the linkages to prevent freezing.

This isn't my understanding of snow brake mode on the units I drive.

If you still do RBTs whilst using the snow brake function then you may as well not bother with the snow brake.

Not sure where you are coming from here.

This isn't a rulebook issue, it's TOC/traction policy. But still - why bother if you're going to do the RBTs anyway?

Hmmmmm. RBTs go back many many years and they are/were based on the traction of the time and because ice would form within the pipes and you would need to blow out the air to keep the pipes free of ice buildup. I would say that the RBTs in the rule book mostly exist purely from a historical perspective. When I first started the requirements for RTBs were pretty extensive (Does ABBBA ring a bell ?) Now my only RBTs are after leaving, but before my first stop and during snowfall. The new style rulebook allows TOCs a greater amount of flexibility and to allow for local stock requirements.
Or am I misunderstanding the snow brake?

Maybe, what is your understanding ?

Mine is that the 'snow brake mode' puts the discs and/or treads in continuous contact so that they warm up and prevent/reduce the build up of ice. This wouldn't prevent ice build up in the pipe or brake cylinders. (which was what the snow RBT was all about)

The last unit I drove with 'Full Service' was a 319 and was still based on the driving principles of 'amps and air' Modern units are very different and I can understand the reduction of the need for RBTs. With the units I drive now I don't need to do a personal brake test (because of a recent mod) and a couple have an 'automatic brake test' and will even self test the DSD.

The secondary reason for doing regular brake tests is so the driver can ensure the brakes are working correctly and get an idea for how much braking performance is affected. The snow brake doesn’t necessarily prove that the brakes are functioning correctly. You don’t want it to be that the only time you’re testing your brakes or getting a feel for them is when you are braking for cautionary signals, station stops or speed restrictions. But as you say, it would be dependant on company and traction.

A couple of recent incidents certainly highlight to see a reduction in speed with a RBT, rather than the more technical reasons for them. I would say that the rulebook caveat that 'whenever the Drivers feels necessary' is appropriate here.
 
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bengley

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Same here.



This isn't my understanding of snow brake mode on the units I drive.



Not sure where you are coming from here.



Hmmmmm. RBTs go back many many years and they are/were based on the traction of the time and because ice would form within the pipes and you would need to blow out the air to keep the pipes free of ice buildup. I would say that the RBTs in the rule book mostly exist purely from a historical perspective. When I first started the requirements for RTBs were pretty extensive (Does ABBBA ring a bell ?) Now my only RBTs are after leaving, but before my first stop and during snowfall. The new style rulebook allows TOCs a greater amount of flexibility and to allow for local stock requirements.


Maybe, what is your understanding ?

Mine is that the 'snow brake mode' puts the discs and/or treads in continuous contact so that they warm up and prevent/reduce the build up of ice. This wouldn't prevent ice build up in the pipe or brake cylinders. (which was what the snow RBT was all about)

The last unit I drove with 'Full Service' was a 319 and was still based on the driving principles of 'amps and air' Modern units are very different and I can understand the reduction of the need for RBTs. With the units I drive now I don't need to do a personal brake test (because of a recent mod) and a couple have an 'automatic brake test' and will even self test the DSD.
You do seem to not be aware of the more recent innovations of snow brake mode particularly on the CAF civity fleet. It cycles the friction brake on each axle individually periodically which solves the problems you mention. It does this even when accelerating
 

ComUtoR

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You do seem to not be aware of the more recent innovations of snow brake mode particularly on the CAF civity fleet. It cycles the friction brake on each axle individually periodically which solves the problems you mention. It does this even when accelerating

Cheers for the further insight. Following on from what I was saying; it makes even more sense that the RBT should be TOC and Traction specific.
 

Intermodal

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The secondary reason for doing regular brake tests is so the driver can ensure the brakes are working correctly and get an idea for how much braking performance is affected. The snow brake doesn’t necessarily prove that the brakes are functioning correctly. You don’t want it to be that the only time you’re testing your brakes or getting a feel for them is when you are braking for cautionary signals, station stops or speed restrictions. But as you say, it would be dependant on company and traction.
I'm talking here specifically about additional RBTs during snow. I understood these were not to determine the braking performance of the train but rather to prevent the freezing of mechanical components in the brakes. If you remove the risk of the freezing via a snow brake function then there should be no reason to do more RBTs than normal just because it is cold (assuming the snow brake does in fact prevent freezing).

Maybe, what is your understanding ?

Mine is that the 'snow brake mode' puts the discs and/or treads in continuous contact so that they warm up and prevent/reduce the build up of ice. This wouldn't prevent ice build up in the pipe or brake cylinders. (which was what the snow RBT was all about)
My understanding was as bengley posted above - that it cycles the brakes on the train, activating each brake cylinder one by one in a continuous 'cycle' throughout the train. I wasn't aware that older traction does not operate in this way and if older traction does simply keep a bit of friction on the braking surfaces then I can of course see that RBTs would be useful to prevent cylinders/air pipes freezing.
 

bengley

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I'm sure on 700s that the snow brake simply increased the blend of friction and reduced the regen braking. Also interesting to note, 700s have tread brakes on the motored axles
 

fulmar

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Source ? Is this TOC specific ?

Cheers in advance.
Yes, TOC / traction specific. On class 195 / 331 the snow brake continuously cycles the brakes throughout the train as mentioned above. I wasn't aware that some units apparently have a "snow brake" that functions differently.
 
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