VB steam locos hauling VB diesels dead

[rodent279]

Morning.

I think this may have been asked before, so apologies in advance.

Diesels, the dual braked flavour, as I understand it, have air brakes on the loco, but vac/air train brakes.

If the loco is dead, with no compressors running, how does a steam loco haul it? Does it run in the train as an unfitted, through piped vehicle?

Edited January 6, 2018 by rodent279

[russ p]

Needs a brake van even if it's a vac only diesel as the bogie brakes are air

[rodent279]

So if a diesel failed on a passenger train, and had to be assisted by steam, it would have to be removed, or hauled unfitted but through piped?

[E3109]

I only know about air brakes so shoot me down here if I deserve it.

But my understanding is that if an air braked loco is to work vac braked passenger stock then provided there is a loco inside that is dual braked to act as a translator, then it can be done.

Thus, my (quite possibly wrong) assumption is that the reverse is also true?

 

Incidentally I know of one example of vac braked diesels that had both vac train brakes and 'vac straight air' if you will. The Malayan EE 20 class, the 'direct brake' (to use imported terminology) was also vacuum on these.

[E3109]

Also. If an air braked loco has jacked and requires assistance then by turning the dead loco into a wagon (by isolating cocks) then it's a pretty simple procedure.

 

As I suggested above, surely the same would be true for vac loco assisting vac loco?

 

Vacuum brakes are before my time, so I can't say for sure.

 

Interesting topic you raised there squire, I look forward to the replies!

[jim.snowdon]

No. In general, diesel and electric locomotives are air braked in their own right, but when they were equipped to operate vacuum brakes on the train, the driver's brake valve is designed to provide proportional application of both the locomotive air brake and the train vacuum brake. Thus, if the locomotive is dead, it has no on-board air supply to operate its own brakes so is effectively a vacuum piped wagon and must be coupled between the locomotive and other vacuum braked vehicles, or a brake van provided.

 

If both locomotives are provided with air braking, the same situation applies unless the locomotive being hauled is provided with the necessary brake valves to allow it to be brakes as just another wagon, ie with automatic air brake instead of driver applied air braking. Class 66s are equipped with the necessary changeover valves so that when a train is topped and tailed, the rear locomotive behaves like a wagon. Failure to set the brake valves correctly has on accasions led to several embarrassing moments, there being at least on RAIB report in recent times concerning a rear locomotive runaway.

 

Jim

[LMS2968]

If the steam loco uses vacuum to the stock and the stock is vacuum braked, the air braked diesel or electric would run as a swinger with no brakes operating on it, being dependent on the braking of the loco in front and the stock behind to provide the brake force. It isn't a popular arrangement, as having 100 odd ton of unbraked weight in the train does not aid stopping distances. I'm not sure what the implications are for TPWS.

[rodent279]

If the steam loco uses vacuum to the stock and the stock is vacuum braked, the air braked diesel or electric would run as a swinger with no brakes operating on it, being dependent on the braking of the loco in front and the stock behind to provide the brake force. It isn't a popular arrangement, as having 100 odd ton of unbraked weight in the train does not aid stopping distances. I'm not sure what the implications are for TPWS.

If in a passenger train, would this lead to a speed restriction?

Edited January 6, 2018 by rodent279

[roythebus]

Several scenarios:

Steam loco (vb) hauling dead diesel/electric loco (ab/vb train only) in the UK, the hauled loco is unfitted, and either required a brake van pre 9172 (I think) or a competent person, 2nd man or guard on the rearmost loco to operate the handbrake on the rearmost loco in the event of a breakaway.

 

One of the jobs I done as a 2nd man at Rugby was to take several electirc locos to Crewe hauled by another electric loco. I had to ride on the rearmost loco. It was shall we say a bit chilly as it was winter. 

 

Steam loco vb hauling vb stock with vb diesel on the back, the diesel loco must either have the engine running to provide air for the loco air brake which will apply in the event of a breakaway or have a competent person ride on the loco to apply the handbrake in the event of a breakaway. The rear loco will be a "swinger" and as LMS2968 says, 100 tons of unbraked loco on the back! 

 

As far as I know all diesel locos in the UK have air brakes for the loco.

 

To go back to an earlier period, locos in multiple, i.e. more than 1 loco controlled from the leading cab with 1 driver, all engines would be running and air/vacuum provided from the leading cab's drivers brake valve, so either air or vacuum application would apply the brakes on the other locos and the train. Locos in tandem, where there is a driver on each loco, the same would apply except there would have to be a driver on each loco to control the power on each loco. Braking is always under control from the leading loco.

 

It is not possible to isolate the vacuum brake on separate vehicles as far as I am aware. This was a trick question I was asked when doing a drivers rules exam on the KESR a few years ago! The only way is to uncouple the vacuum pipes in front of the defective vehicle and run the rest of the train a unfitted.<waits for a list of vehicles fitted with vacuum isolating cocks to appear>..

Edited January 6, 2018 by roythebus

[roythebus]

If in a passenger train, would this lead to a speed restriction?

I don't think so but am not conversant with current Network Rail rules. as for the TWPS, I presume that this would be isolated on the rear loco along with the DSD and any other vigilance devices. I know on the KESR DMMU we have to isolate the DSD before shunting it round the yard as the DSD speed sensor will operate one it reaches 5mph and drop the vacuum.

[rodent279]

Never thought it would be such a minefield!

Edited January 6, 2018 by rodent279

[russ p]

When did vans become mandatory for dead locos Roy? Wouldn't fancy trying to stop a runaway loco with its handbrake as most are crap

The only diesels I can think of that were vac braked were the LMS co-cos their Bo-bo NBL and I think the fell not sure whether that Armstrong whitworth loco was too

[Steamport Southport]

About 4:30 minutes in. Dead diesel getting dragged back to works.

 

https://www.youtube.com/watch?v=Lm7tBvKpjxo

 

 

 

Jason

[russ p]

Poor frozen second man taking his life in his hands!

[The Bigbee Line]

Several scenarios:

Steam loco (vb) hauling dead diesel/electric loco (ab/vb train only) in the UK, the hauled loco is unfitted, and either required a brake van pre 9172 (I think) or a competent person, 2nd man or guard on the rearmost loco to operate the handbrake on the rearmost loco in the event of a breakaway.

 

One of the jobs I done as a 2nd man at Rugby was to take several electirc locos to Crewe hauled by another electric loco. I had to ride on the rearmost loco. It was shall we say a bit chilly as it was winter. 

 

Steam loco vb hauling vb stock with vb diesel on the back, the diesel loco must either have the engine running to provide air for the loco air brake which will apply in the event of a breakaway or have a competent person ride on the loco to apply the handbrake in the event of a breakaway. The rear loco will be a "swinger" and as LMS2968 says, 100 tons of unbraked loco on the back! 

 

As far as I know all diesel locos in the UK have air brakes for the loco.

 

To go back to an earlier period, locos in multiple, i.e. more than 1 loco controlled from the leading cab with 1 driver, all engines would be running and air/vacuum provided from the leading cab's drivers brake valve, so either air or vacuum application would apply the brakes on the other locos and the train. Locos in tandem, where there is a driver on each loco, the same would apply except there would have to be a driver on each loco to control the power on each loco. Braking is always under control from the leading loco.

 

It is not possible to isolate the vacuum brake on separate vehicles as far as I am aware. This was a trick question I was asked when doing a drivers rules exam on the KESR a few years ago! The only way is to uncouple the vacuum pipes in front of the defective vehicle and run the rest of the train a unfitted.<waits for a list of vehicles fitted with vacuum isolating cocks to appear>..

You can isolate a vacuum braked wagon. One of the flexible pipes underneath is cut and a wooden cone (like a small spinning top) is tapped in the pipe to allow the vacuum to be created in the pipe.  Had that done a few times in the 80's at Hither Green in the middle of the night with Minfits ex Betteshanger.  Until recently I had one of the wooden cones..

[roythebus]

When did vans become mandatory for dead locos Roy? Wouldn't fancy trying to stop a runaway loco with its handbrake as most are crap

The only diesels I can think of that were vac braked were the LMS co-cos their Bo-bo NBL and I think the fell not sure whether that Armstrong whitworth loco was too

 

I reckon pre-1972, before ASLEF accepted guards riding in the back cabs of locos, but I may be wrong. As stated, otherwise a competent person of the footplate grade I'd say.

 

ISTR the LMS locos were air braked on the locos, I remember going on them when they were in store at Willesden TMD, late 1960s. As for the others, before my time!

Edited January 7, 2018 by roythebus

[roythebus]

You can isolate a vacuum braked wagon. One of the flexible pipes underneath is cut and a wooden cone (like a small spinning top) is tapped in the pipe to allow the vacuum to be created in the pipe.  Had that done a few times in the 80's at Hither Green in the middle of the night with Minfits ex Betteshanger.  Until recently I had one of the wooden cones..

Yes agreed, but it's not isolated as with the provision of an isolating cock like air brakes have.

[45125]

You can isolate a vacuum braked wagon. One of the flexible pipes underneath is cut and a wooden cone (like a small spinning top) is tapped in the pipe to allow the vacuum to be created in the pipe.  Had that done a few times in the 80's at Hither Green in the middle of the night with Minfits ex Betteshanger.  Until recently I had one of the wooden cones..

 

If done by a C&W examiner the release valve would be undone and a not go (or similar) label would be inserted across the valve face ant the valve refitted or the top of the D/A valve would be taken off and a not go label put across the valve face and the top pot on upside down.

[Mark Saunders]

If done by a C&W examiner the release valve would be undone and a not go (or similar) label would be inserted across the valve face ant the valve refitted or the top of the D/A valve would be taken off and a not go label put across the valve face and the top pot on upside down.

Inoperative brakes is not a reason to Red Card a wagon as it is still fit to run if marshalled correctly to repair point!

[45125]

A vac braked steam loco was sent to assist a diesel or electric if it was coupled on the head off the train, the dead loco would need its air brakes releasing and the AV2 isolating the steam loco would the blow the vac brake off the train and move forward with due regard to available brake force etc. The main problem would be assisting a light loco, then various things come in to play such as assisting from the rear, is the failed loco fully dead ie not flat batteries.

[roythebus]

A vac braked steam loco was sent to assist a diesel or electric if it was coupled on the head off the train, the dead loco would need its air brakes releasing and the AV2 isolating the steam loco would the blow the vac brake off the train and move forward with due regard to available brake force etc. The main problem would be assisting a light loco, then various things come in to play such as assisting from the rear, is the failed loco fully dead ie not flat batteries.

 

There's always a brake release valve. Marked on rolling stock with a white star on the solebar.  Steam on front of diesel/electric, the steam loco can pull the lot as an unfitted train to the nearest station to detrain passengers after the brakes have been individually released, providing there is a brake coach at the rear of the train. If not, assistance must be in the rear to provide a brake in case of a runaway. It all depends on the combination of locos, brakes and rolling stock.

 

A quick tale from the past when I was a driver at Waterloo in the 1980s, driving a VEP/whatever (EP and Westinghouse air brake) to Reading, approaching Wokingham, just wondering what would I do if I had to assist a DEMU (vacuum brake only)  towards Reading. Got stopped at the signal protecting the junction, signalman told me the preceding DEMU had failed in section..Ha, I knew exactly what to do, having just been thinking about it.

 

Problem solved, the bobby told me he'd keep me there as the next DEMU was only 10 minutes away and would assist the failed unit to Reading. Simples.

 

Assisting light loco, couple up other loco front or rear, apply handbrake, release loco air brake, isolate DSD/AV2, driver remains on dead loco, releases handbrake, 2 locos clear off. Driver applies handbrake in emergency. Not forgetting detonator protection, but that's another story.

Edited January 9, 2018 by roythebus

[Titan]

All DEMUs are air brake only.

[The Stationmaster]

Inoperative brakes is not a reason to Red Card a wagon as it is still fit to run if marshalled correctly to repair point!

 

It should be a red & green label on a wagon for a vac brake isolation if memory serves me right.

[Covkid]

 

 

ISTR the LMS locos were air braked on the locos, I remember going on them when they were in store at Willesden TMD, late 1960s. As for the others, before my time!

 

I am going to disagree Roy. My Bachmann model of 10001 has a vacuum cylinder inboard of each bogie on the underframe. Bachmann could have got it wrong of course but I somehow doubt it. I therefore turned to MLI 185 and swotted up. The Graham Fenn drawing shows vacuum cylinders as I mentioned on the Bachmann model, but CJM states "Brake equipment was supplied by Westinghouse with air controlling the brakes on the locomotive and vacuum brakes provided for the trains". 

 

I appreciate that indifferent comments have been made about both CJM scribings and Graham Fenn drawings, but I am inclined to believe that the Ivastt "twins" were vacuum braked, but willing to be proved wrong.

[Covkid]

Whilst on the subject I have seen an image of an B1 4-6-0 hauling an BR class AL5 into Derby, presumably from Doncaster. The AL5 was braked by air and would have needed air to be supplied to it, but not sure how many, if any B1s were fitted with Westinghouse air pumps, this late in their career. In my view the AL5 would almost certainly have been a "swinger" and the shackle would probably have been wound up tight !!