FGW HST hits tree

[No Fault Found]

Yes, each car has its own WSP rack that monitors the axles.

So under what circumstances would they all lock? Could it be a train wire fault?

 

[Old Timer]

For what it's worth - I've never known a train to have all wheels lock up either. But I'm not saying it's never happened - like O L Leigh says, just my own experience to go by. It's the only one I trust!

HSTs have enhanced braking, and when the brake controller is placed to Emergency it shuts down any form of WSP.

I believe it is now an irrecoverable brake application, in that it cannot be released until the train has stopped.

Whilst it would be unlikely that EVERY wheelset locked up, I can understand a number. However all things are possible and I am sure that time will reveal the final accurate details.

 

[The_Stig]

So under what circumstances would they all lock? Could it be a train wire fault?

I agree with TDK, in an emergency situation when the full brake pressures are applied onto the wheels and there is poor cohesion then it is possible for all the wheels to lock. On an EMU IIRC its the second axle that sends the signals to the speedo, so if this stays locked even after WSP activity the train will assume it is at a standstill.

Having seen the damage caused it is possible that if the WSP rack was in the cab it was damaged and therefore unable to send a reference signal to the other WSP units. This could also explain the full lock. I am guessing however.

 

[Old Timer]

I agree with TDK, in an emergency situation when the full brake pressures are applied onto the wheels and there is poor cohesion then it is possible for all the wheels to lock. On an EMU IIRC its the second axle that sends the signals to the speedo, so if this stays locked even after WSP activity the train will assume it is at a standstill.

Having seen the damage caused it is possible that if the WSP rack was in the cab it was damaged and therefore unable to send a reference signal to the other WSP units. This could also explain the full lock. I am guessing however.

Emergency takes WSP out of use !!!!!

 

[The_Stig]

Emergency takes WSP out of use !!!!!

On an EMU?

 

[Old Timer]

Which again makes it look like you're saying the HST squadron services started in 73...
Just to be sure I'm not reading it well, I got to other people to read it too. They both agreed with me.

My sentence is entirely grammatically correct. I suggest that you think about the fact that there are multiple commas in there and speak it out aloud in the way it is punctuated, then it will mkae sense.

...I can note commas, ta. Got an A* in my English coursework....

No need to get tetchy as I was not being sarcastic, however on the basis that you have what you claim I am somewhat surprised to be having this conversation.

On the basis of the standard of punctuation and indeed grammar now taught, and reflected in the standards I see in letters and CVs from both school-leavers and graduates I can only assume a dumbing down in the quality of teaching these days.

At least one University now has a whole course devoted to teaching its intake on the three Rs.

 

[O L Leigh]

I have never understood how shutting down the WSP when hitting Emergency can be considered an "enhancement". Surely you want the train to stop as quickly as possible and a locked wheelset isn't contributing a lot of brakeforce. It's certainly the case with the units I drive that the WSP and auto-sanders do work in ALL brake steps above Step 1, and that includes Emergency, and that seems like the most sensible way to have it.

Going for emergency is indeed now irrecoverable on most if not all trains, and I expect it's the same with HST's. Trains are now fitted with a Speed Switch which engages and disengages at a certain speed, usually 5-10mph. If you go for an E brake application above this speed it will not release until a certain time period elapses. On our units this used to be 2 minutes, but it was contributing massively to delays and so was reduced to about 15 seconds or so. But the problem now is that the E brake can time-out and release before the train has come to a stand, so if we get an unsolicited E brake application (e.g. due to a loss of interlock) we have to put the brake handle into Emergency until the train has stopped.

O L Leigh

 

[TGV]

Not all types of train have WSP isolated in such cases. And I was just typing that I can see O L Leigh agrees with my thought that there's no benefit to this (it's like the ABS in your car decides to de-activate on high brake force application). In such rail applications when an emergency brake application is made on the rolling stock I have worked on, you'll get all friction brakes and rheo/regen brakes all on at once until ~5km/h when the control is handed back to the driver (of course the rheo/regen will cease at about 40km/h) but the WSP is still very much active all the way. However I understand that this strange situation seems to apply to the HST which is the train in question. I just can't see the benefit of it.

 

[O L Leigh]

I agree with TDK, in an emergency situation when the full brake pressures are applied onto the wheels and there is poor cohesion then it is possible for all the wheels to lock.

Yes it is possible for an all-wheel slide, but highly unlikely. The conditions would have to be spectacularly bad just at that location to have prompted such an event.

On an EMU IIRC its the second axle that sends the signals to the speedo, so if this stays locked even after WSP activity the train will assume it is at a standstill.

If this is the case on some EMU classes it must be very rare. The units I drive take the speedo drive from the leading wheelset. This is a very good indicator of the onset of a slide because it shows in the cab as a bouncing speedo needle. Sometimes it will indeed drop straight to zero and stay there.

Even if the train were in a position to assume anything about it's speed, this has no bearing on the braking performance. The Cl450 that had a double SPAD at Esher a few years back was almost certainly in an all-wheels slide (or at least very close to one) and yet the E brake was maintained and the WSP was active throughout.

Having seen the damage caused it is possible that if the WSP rack was in the cab it was damaged and therefore unable to send a reference signal to the other WSP units. This could also explain the full lock. I am guessing however.

Each vehicle will have a WSP rack of it's own that operates independently of all the other vehicles in the train. It is usually located below the solebar and not in the train cabs.

O L Leigh

 

[Old Timer]

I have never understood how shutting down the WSP when hitting Emergency can be considered an "enhancement". Surely you want the train to stop as quickly as possible and a locked wheelset isn't contributing a lot of brakeforce. It's certainly the case with the units I drive that the WSP and auto-sanders do work in ALL brake steps above Step 1, and that includes Emergency, and that seems like the most sensible way to have it.

O L Leigh

I seem to recall an issue with the Edinburgh/Glasgow Push-Pull sets when hauled by the Class 27s. Those sets were equipped with the first series of WSP protection and it could be heard operating when they came into a station "hard".

I recall the issue was that the braking distance was extended through WSP activation, because it blew the brake off each axle if it stopped rotating.

WSP was designed to protect the wheelset from damage, NOT to assist in the stopping of the train, hence the reason why WSP was taken out when in Emergency.

Tests back in the mid to late 70s on the GN between Hitchin and Sandy demonstrated that in slippery rail conditions, a service brake application with operation of the WSP WOULD bring the train to a stand as only the first few axles were being affected by the rail head conditions.

Of course now that we have vegetation actually growing in the four-foot, and an unwillingness to provide any form of tread brake, the problem is much different.

From what I was told when I last discussed this with a driver, in a prolonged slide, the drivers were instructed to go to Step 3 and if there was no retardation after a period to then go to Emergency and vacate the cab if appropriate and expedient to do so.

I have been hunting through the RGS to find the relevant section on WSP but it appears to be hiding at the moment.

Going back to the HST I anticipate that it is still conventionally braked i.e. with MRP and with the BP controlled by the MRP/distributor ?

 

[The_Stig]

Yes it is possible for an all-wheel slide, but highly unlikely. The conditions would have to be spectacularly bad just at that location to have prompted such an event.

Very true. Since the weather was particularly bad and the trees had branches snapped off it is very concievable that the tracks were covered in foliage, allowing for such an occurrence.

If this is the case on some EMU classes it must be very rare. The units I drive take the speedo drive from the leading wheelset. This is a very good indicator of the onset of a slide because it shows in the cab as a bouncing speedo needle. Sometimes it will indeed drop straight to zero and stay there.

Apologies, I meant to say that. Speed reference is taken from the second axle in the direction of travel.

Even if the train were in a position to assume anything about it's speed, this has no bearing on the braking performance. The Cl450 that had a double SPAD at Esher a few years back was almost certainly in an all-wheels slide (or at least very close to one) and yet the E brake was maintained and the WSP was active throughout.

WSP has no control over the brakes. If a brake application is made, irrelevant of step/position in the braking arc. WSP merely dumps air (for a very short period) from the brake actuators on the affected axle, allowing the wheel to start turning again. The brake pressure will remain the same throughout the unaffected axles and will be re-applied to the affected axle after it starts to rotate.

Each vehicle will have a WSP rack of it's own that operates independently of all the other vehicles in the train. It is usually located below the solebar and not in the train cabs.

O L Leigh

Yes.

PS- The 320's WSP racks are in the saloons.

 

[O L Leigh]

I seem to recall an issue with the Edinburgh/Glasgow Push-Pull sets when hauled by the Class 27s. Those sets were equipped with the first series of WSP protection and it could be heard operating when they came into a station "hard".

I recall the issue was that the braking distance was extended through WSP activation, because it blew the brake off each axle if it stopped rotating.

Interesting stuff.

I might just be making an assumption, but that suggests to me that the WSP was too sensitive on these sets. A locked wheelset provides only marginally more brakeforce than an unbraked one, so lengthened braking distances suggests that the WSP was releasing too early.

Either that or the drivers were attempting to prove themselves better than the system and deliberately trying to undermine it's performance.

From what I was told when I last discussed this with a driver, in a prolonged slide, the drivers were instructed to go to Step 3 and if there was no retardation after a period to then go to Emergency and vacate the cab if appropriate and expedient to do so.

Yes, that's what we were told also.

However, from a driver's perspective, going up through the steps really is just for the benefit of the OTMR. If it's sliding badly in Step 2, is there really going to be enough adhesion to take an even higher brake step...? But by going up through the steps you can at least demonstrate that you did all you could.[/quote]

Going back to the HST I anticipate that it is still conventionally braked i.e. with MRP and with the BP controlled by the MRP/distributor ?

Not being lucky enough to "sign" HST's, I'm not in a position to comment.

I meant to say that. Speed reference is taken from the second axle in the direction of travel.

Not necessarily. Some of the more modern WSP systems use an in-built "5th wheelset" that simulates electronically the actions of the reference set to estimate the true train speed.

WSP has no control over the brakes. If a brake application is made, irrelevant of step/position in the braking arc. WSP merely dumps air (for a very short period) from the brake actuators on the affected axle, allowing the wheel to start turning again. The brake pressure will remain the same throughout the unaffected axles and will be re-applied to the affected axle after it starts to rotate.

Sorry, I think I may have been a bit vague in my previous post.

What I was trying to say was that the Cl450 that slid past two at Esher had maintained an E brake demand throughout the slide and WSP was also active throughout the slide. Even though it was not possible to determine from the train's OTMR if it had indeed been in an all-wheel slide, at least one vehicle was. This might have lead the WSP to assume that the train had come to a stand, but it didn't and so it continued to function.

I am familiar with the mechanics of the WSP system. It's saved my bacon once or twice.

PS- The 320's WSP racks are in the saloons.

Ah, um...

No, I'm afraid they're not (click). That box just below the leading set of doors is the WSP rack.

O L Leigh

 

[The_Stig]

Not necessarily. Some of the more modern WSP systems use an in-built "5th wheelset" that simulates electronically the actions of the reference set to estimate the true train speed.

O L Leigh

Yes, you are talking about the "Calculated true train speed".

It is only used when there are varying levels of grip between axles, its not used all the time. As I understand it anyway.
--- old post above --- --- new post below ---

Ah, um...

No, I'm afraid they're not (click). That box just below the leading set of doors is the WSP rack.

O L Leigh

That is the brake 4 step relay valve.

 

[Old Timer]

Interesting stuff.

I might just be making an assumption, but that suggests to me that the WSP was too sensitive on these sets. A locked wheelset provides only marginally more brakeforce than an unbraked one, so lengthened braking distances suggests that the WSP was releasing too early.....

Ah but that was the point. The WSP was nothing to do with braking at all.

WSP was provided simply to protect the wheelset, so if you went into a heavy application the WSP just kept on cycling until the train stopped.

Remember years ago starting was our problem, not stopping.

I appreciate I am teaching Grandmother here, but its only the ingress of foliage together with the lack of any wheel scrubbing system (like a brake block) that has caused the problem.

If the lineside foliage was cut back, as it used to be, then we would not have the number of problems we now have with bank stability and adhesion.

We have now had an influx of the wrong kind of managers into the Industry. Remove the porblem at source is what the safety manual tells you to do !

By the way THIS and THIS is what a well maintained Railway looks like

 

[The_Stig]

Under the nearest doors you see two boxes. The farthest away is the 4 step relay valve, the one beside it is the 318 WSP rack.

 

[O L Leigh]

No, you're right. The different shaped cover confused me for a moment because I'm used to seeing them rounded and not quite so angular.

However, the WSP rack is still there just by the Westcode 3 step relay. It's just that I'm struggling to find a pic of a Cl320 to show this. Would you accept a pic of the similar Cl321 showing both boxes below the leading doors...?

O L Leigh

 

[The_Stig]

No, you're right. The different shaped cover confused me for a moment because I'm used to seeing them rounded and not quite so angular.

However, the WSP rack is still there just by the Westcode 3 step relay. It's just that I'm struggling to find a pic of a Cl320 to show this. Would you accept a pic of the similar Cl321 showing both boxes below the leading doors...?

O L Leigh

Trust me, the WSP rack is in the saloon of the 320. Its the only unit I know it is there.

 

[O L Leigh]

Ah but that was the point. The WSP was nothing to do with braking at all.

WSP was provided simply to protect the wheelset, so if you went into a heavy application the WSP just kept on cycling until the train stopped.

Quite. But the situation remains that WSP is an aid to braking in low adhesion conditions whether that was the intention or not.

Remember years ago starting was our problem, not stopping.

It still is.

I appreciate I am teaching Grandmother here, but its only the ingress of foliage together with the lack of any wheel scrubbing system (like a brake block) that has caused the problem.

If the lineside foliage was cut back, as it used to be, then we would not have the number of problems we now have with bank stability and adhesion.

We have now had an influx of the wrong kind of managers into the Industry. Remove the porblem at source is what the safety manual tells you to do !

We're getting back there, but I agree that the law doesn't always help us. Vegetation control is something that has come back into vogue, and there have been sections of our route that have been comprehensively deforested. However, there are still the trees and other vegetation outside of the boundary fence that Nitwit Rail can do little about.

The Stig: I've not forgotten about your Cl320's. I'm still trying to find a sufficiently clear pic of such a unit because there is definately a box under there just by the 3 step relay where the WSP rack would be on similar classes of EMU, but I can't see precisely what it might be.

I am confused as to why a class of unit that is virually identical to all the other Mk3 units of the same vintage should have it's WSP rack in a non-standard location. I understand what you say about seeing a box in the saloon, but do you know for certain what's in it? If it really is the WSP there should be one per coach.

O L Leigh

 

[The_Stig]

The Stig: I've not forgotten about your Cl320's. I'm still trying to find a sufficiently clear pic of such a unit because there is definately a box under there just by the 3 step relay where the WSP rack would be on similar classes of EMU, but I can't see precisely what it might be.

I am confused as to why a class of unit that is virually identical to all the other Mk3 units of the same vintage should have it's WSP rack in a non-standard location. I understand what you say about seeing a box in the saloon, but do you know for certain what's in it? If it really is the WSP there should be one per coach.

O L Leigh

You are correct, I cannot remember off the top of my head what it is, but it is too small for the WSP rack. Its also a 4 step relay valve as there are 4 steps- Step(s)1, 2, 3 (Full service) and Emergency.

There is a WSP rack in each coach, all in the saloon. It is strange why they decided to put the rack in the coach after the 318 and then revert to the under coach approach for the 321/322!

I had posted the way to ID the rack previously but removed it from my post in-case this was the reason why it was put on the underframe, to stop undesirables interfering with it.

 

[O L Leigh]

There's not much the toe-rags can do with a WSP rack anyway, so I suspect it's safe enough in the saloon. The worst that could happen is that they bodge something that causes the relevant MCB to trip or generate a fault, and that's a sure-fire way to attract the attention of the driver because it will cut the power to the motors.

Incidentally, it really is a 3 step relay. I know there are actually four brake steps (five if you include "Release"), but that's what it is called in all the literature and manuals. I suspect that it has something to do with the three brake wires that are energised and de-energised in sequence to provide the various brake steps.

O L Leigh

 

[The_Stig]

There's not much the toe-rags can do with a WSP rack anyway, so I suspect it's safe enough in the saloon. The worst that could happen is that they bodge something that causes the relevant MCB to trip or generate a fault, and that's a sure-fire way to attract the attention of the driver because it will cut the power to the motors.

I think it is because it could end up costing the TOC a lot of cash turning/replacing flat wheels rather than an actual safety issue.

Incidentally, it really is a 3 step relay. I know there are actually four brake steps (five if you include "Release"), but that's what it is called in all the literature and manuals. I suspect that it has something to do with the three brake wires that are energised and de-energised in sequence to provide the various brake steps.

O L Leigh

Depends on the unit. 314's (as I have been told) have 3 step valves, even though there are 4 positions. Steps 1, 2, 3 and Emergency, as normal. Step 3 and Emergency are the same brake pressures (therefore its only a 3 step valve) but there are other factors that make an 'Emergency' situation.

Other units have the 3 steps plus Emergency, Emergency being a higher pressure applied to the brake actuators thus making it a 4 step valve.

 

[O L Leigh]

I think it is because it could end up costing the TOC a lot of cash turning/replacing flat wheels rather than an actual safety issue.

Do you know how far a train in an all-wheel slide can go...?

We used to have problems at one of our stations because it was in the bottom of what is actually a fairly modest dip, but at 2tph off peak it didn't get enough traffic to keep the railhead clean. Drivers would creep around the junction at about 15mph or less, apply the brake nice and gently and immediately get into an all-wheel slide. Then, because of the gradient, they would ACCELERATE down the hill through the station and come to a stand halfway up the hill at the other side almost a mile after the driver had first applied the brakes. Even when they called out the sandite train matters were not improved. After the sandite had run the first train would stop, then the second train would stop (just) but then we'd be back to square one. In the end the station was routinely closed during the autumn.

Depends on the unit. 314's (as I have been told) have 3 step valves, even though there are 4 positions. Steps 1, 2, 3 and Emergency, as normal. Step 3 and Emergency are the same brake pressures (therefore its only a 3 step valve) but there are other factors that make an 'Emergency' situation.

Other units have the 3 steps plus Emergency, Emergency being a higher pressure applied to the brake actuators thus making it a 4 step valve.

All our units give a higher brake pressure in Emergency, and yet it is still called a Westcode 3 step relay in spite of this.

But we're splitting hairs.

O L Leigh

 

[The_Stig]

All our units give a higher brake pressure in Emergency, and yet it is still called a Westcode 3 step relay in spite of this.

You are most probably correct and I have mis-understood!

But we're splitting hairs.

O L Leigh

Agreed!

 

[O L Leigh]

You are most probably correct and I have mis-understood!

It's just the names for things. I know what you're saying though, because it doesn't seem very logical to me either. But it's nothing to fall out over so I'm not concerned.

Mind you, our units were all subject to a mod known at the time as "12% G", or somesuch. This did indeed give a higher brake pressure in Emergency than was the case before, but it was tied to the introduction of Speed Switches that made going for the E brake irrecoverable to dissuade drivers from using it as a matter of course.

However, the brake pressures had been turned down from the levels they were at when our trains were new, so a pressure increase for the E brake was welcomed. Some of the "lifers" remember the Cl315's when they were brand new and recall how you could hit a platform up ramp at 50mph and still be able to stop on the mark. Mind you this did contribute to the number of slides experienced, as the brakes were often too fierce for the railhead conditions (even in Step 1) and would often break adhesion.

O L Leigh

 

[The_Stig]

It's just the names for things. I know what you're saying though, because it doesn't seem very logical to me either. But it's nothing to fall out over so I'm not concerned.

Mind you, our units were all subject to a mod known at the time as "12% G", or somesuch. This did indeed give a higher brake pressure in Emergency than was the case before, but it was tied to the introduction of Speed Switches that made going for the E brake irrecoverable to dissuade drivers from using it as a matter of course.

O L Leigh

Yeah, I remember being told of this. Drivers frequently using emergency when they should not, to gain some ground if late!

The standard (at the time) was a 2 min delay IIRC. This was not kept for long as TOC's were often hit with hefty fines for holding up other traffic!
--- old post above --- --- new post below ---
Sorry Woody if your thread has veered off topic!

 

[O L Leigh]

The standard (at the time) was a 2 min delay IIRC. This was not kept for long as TOC's were often hit with hefty fines for holding up other traffic!!

Yes indeed. I got caught out by just this feature on an 8 car Cl315 formation a few years back. I ended up blocking the entire west side of Liv St and the Suburban and Main lines when I dropped the DSD as I went out through the station throat and sat there like a plum waiting for the brakes to time out.

The time-out is much shorter now.

O L Leigh

 

[crewmeal]

Anyone know how FGW are coping without this set? Did they hire in anything unusual?

 

[moonrakerz]

Moonrakerz
This whole fixation people such as you have with the Daily Mail would actually be quite funny if it were not so serious...............................
None of the above is a personal attack upon you by the way, you are free to live your life as you wish as far as I am concerned and hold whatever beliefs you want, but simply some observations as they appear to me.

I won't "quote" the whole of your post as it appears to have now descended into a pseudo-political diatribe.

However, it does seem to contain, most eloquently, my original comment to the effect "don't believe everything you read in the papers".
--- old post above --- --- new post below ---

I expect it was the only thing available at Westbury to do the job!

I did see an 08 there a few days ago.

 

[Dreadnought]

I did see an 08 there a few days ago.

The 08 at Westbury is apparently broken and they now have 60049 for shunting duties.

 

[kestrel]

Which again makes it look like you're saying the HST squadron services started in 73...

I can note commas, ta. Got an A* in my English coursework.

Just to be sure I'm not reading it well, I got to other people to read it too. They both agreed with me.

I've read it several times and reads very well, BEFORE squadron service ie it is in the depot and not in service ie means built and operational but NOT in public service.......simples really!