Putting a Steam Engine in reverse for emergency stop

[kermit]

The You Tube algorithm proved (once again) its terrifying accuracy by suggesting I might be interested in a clip from the classic 1950s American black-and-white TV series, Casey Jones. But this prompted a long lost memory, that when Casey needed to bring the Cannonball Express to a sudden stop (ie in almost every episode), he would put the engine in reverse, causing the wheels to "slip" backwards. Is or was that a real actual driving technique?

 

[mike57]

My basic understanding from Physics (but it was 50 years ago) is that once the two surfaces slip rather than maintain contact the friction is reduced and torque transmission would then be lower, so lowering braking force. Others may be able to elaborate further as there could be other issues coming into play as well.

 

[Merle Haggard]

I think that there's a misunderstanding here.

Reading old accident reports on Railways Archives, in the days when braking, even of passenger trains, relied on the loco tender's brake and guard - operated brakes in a brake van, recourse was often made to 'applying reverse steam'.

However, the idea was not to make the wheels spin in reverse direction. I find it a bit hard to explain in words, but the principle was that by applying steam in reverse gear, the steam pressure acted against the moving pistons, slowing them down and providing retardation. In other words, forward momentum was absorbed by the pistons trying to compress further the steam being sent into the cylinders. The coupled wheels continued to revolve in the direction of travel.

 

[gg1]

I think that there's a misunderstanding here.

Reading old accident reports on Railways Archives, in the days when braking, even of passenger trains, relied on the loco tender's brake and guard - operated brakes in a brake van, recourse was often made to 'applying reverse steam'.

However, the idea was not to make the wheels spin in reverse direction. I find it a bit hard to explain in words, but the principle was that by applying steam in reverse gear, the steam pressure acted against the moving pistons, slowing them down and providing retardation. In other words, forward momentum was absorbed by the pistons trying to compress further the steam being sent into the cylinders. The coupled wheels continued to revolve in the direction of travel.

Sounds similar in effect (though with a different mechanical principle behind it) to using engine braking in a car by changing into progressively lower gears.

 

[Taunton]

Reading old accident reports on Railways Archives, in the days when braking, even of passenger trains, relied on the loco tender's brake and guard - operated brakes in a brake van, recourse was often made to 'applying reverse steam'.

Not only on unbraked freight trains, it was a common technique all round. David L Smith's classic books about the G&SW more than 100 years ago describe it multiple times.

I'm sure someone here can explain how it was compatible with applying the loco brakes themselves, and even with using steam sanders, all in combination, as it does seem to put considerable stress on the coupling rods.

 

[kermit]

Thanks for the replies. Even as a youngster watching Casey Jones I think I grasped that if the wheels were going round in reverse, they weren't likely to be doing much stopping of the train, and what I was seeing was probably more for dramatic effect. However, my understanding from the replies above is that it is perfectly possible to put a steam loco in reverse while the wheels are going forwards (very much not like a car!), and the trick would have been to apply enough reverse force without allowing the wheels to slip (and indeed if the reverse slipping ran away uncontrolled, damage to the engine would ensue). So would it still be done if, for instance, a main line steam excursion needed to stop in a hurry?

 

[Taunton]

it is perfectly possible to put a steam loco in reverse while the wheels are going forwards (very much not like a car!), and the trick would have been to apply enough reverse force without allowing the wheels to slip (and indeed if the reverse slipping ran away uncontrolled, damage to the engine would ensue).

There was doubtless more to it, and I suspect that as speed fell off there would be a greater likelihood of the wheels reverse-rotating. There's a lot more in the subject to know. Jeremy Clarkson when riding Tornado from Kings Cross to Edinburgh was amazed to get wheelslip suddenly at 70mph. Author David L Smith, again, described a driver demoted after a coupling rod breakage (expensive and dangerous) because he told Hugh Smellie, chief engineer of the G&SW around 1900, that it was slipping with the steam shut off, and Smellie didn't believe that - which Smith says showed Smellie didn't know everything about steam locomotives. I still haven't understood yet how that could happen.

But for Hollywood ... how else to show the train is starting, or stopping? Technique used in multiple films.

 

[jamieP]

Thanks for the replies. Even as a youngster watching Casey Jones I think I grasped that if the wheels were going round in reverse, they weren't likely to be doing much stopping of the train, and what I was seeing was probably more for dramatic effect. However, my understanding from the replies above is that it is perfectly possible to put a steam loco in reverse while the wheels are going forwards (very much not like a car!), and the trick would have been to apply enough reverse force without allowing the wheels to slip (and indeed if the reverse slipping ran away uncontrolled, damage to the engine would ensue). So would it still be done if, for instance, a main line steam excursion needed to stop in a hurry?

It definitely would not be done today. Air or vacuum brakes do a much better job of slowing a train down than putting the loco in reverse.

 

[E27007]

There was doubtless more to it, and I suspect that as speed fell off there would be a greater likelihood of the wheels reverse-rotating. There's a lot more in the subject to know. Jeremy Clarkson when riding Tornado from Kings Cross to Edinburgh was amazed to get wheelslip suddenly at 70mph. Author David L Smith, again, described a driver demoted after a coupling rod breakage (expensive and dangerous) because he told Hugh Smellie, chief engineer of the G&SW around 1900, that it was slipping with the steam shut off, and Smellie didn't believe that - which Smith says showed Smellie didn't know everything about steam locomotives. I still haven't understood yet how that could happen.

But for Hollywood ... how else to show the train is starting, or stopping? Technique used in multiple films.

The steam circuit between the regulator valve and the cylinder block has a significant volume, perhaps the volume of steam is adequate to continue to drive the pistons after the regulator is closed

 

[Taunton]

Yes, but as soon as you shut off the pressure in the circuit is going to start falling, making slipping unlikely. Smith also wrote about locos that could, very occasionally, carry on steaming after the steam was shut off, apparently a known feature of a particular designer's steam circuit, but which came as a considerable surprise to some drivers.

 

[DerekC]

Early locos often had brakes only on the tender, as I recall, so putting the locomotive into reverse would add considerably to the braking force available. In fact I think this was the accepted way to stop. Certainly "reversing the motion" is described in several places in the early chapters of L T C Rolt's immortal "Red for Danger" to try to avoid a collision.

 

[Narrowgauge725]

Standard practice at my railway is to put the reverser two notches back from dead centre with the drain cocks open to do most of the braking on downhills sections. No steam is applied as the cylinders are acting as compressors which provides the braking force.

 

[43096]

It definitely would not be done today. Air or vacuum brakes do a much better job of slowing a train down than putting the loco in reverse.

A number of the early AC electric locos were written off with fire damage, the suggestion being old hand steam men had put them into reverse to stop.

 

[Ashley Hill]

I would think that doing this would put immense strain on the motion. Surely this would only be done in an emergency such as a runaway after all other methods had failed.

 

[Narrowgauge725]

I would think that doing this would put immense strain on the motion. Surely this would only be done in an emergency such as a runaway after all other methods had failed.

No motion is designed to drive the loco so much more force to drive it.

 

[E27007]

It definitely would not be done today. Air or vacuum brakes do a much better job of slowing a train down than putting the loco in reverse.

My thoughts too, for dramatic effect, and perhaps to minimise wear to the tyres, the head of the rail was treated with a lubricant

 

[midland1]

Have a quick look at the film Train of Events 1949, the accident scene can be seen on Youtube

 

[ChiefPlanner]

Observe the excellent "The Train" (1964) when persued by a Spitfire , the light engine races into a tunnel where a very firm Westinghouse application is made , then the engine is put into reverse ! - (counter productive I guess - but allowing for limited brake force with no load behind it would take a bit of stopping - looks good on screen though)

The other odd bit in the film - just before the spectacular , contrived crash at Rives-Rheine , the moving train is uncoupled on the move (riskily) - without a very full brake application , once the screw couplings and air lines have been shut (cocks closed) are parted.

Would a big ejector somehow manage to counteract this ? Pretty sure it was not in the BR Appendix for working the air brake ????

 

[dgl]

I suppose this is somewhat akin to dynamic braking on trains with electric motor drives, as you are still technically running the train in reverse so as to use the drive train to assist with braking.

 

[kermit]

I suppose this is somewhat akin to dynamic braking on trains with electric motor drives, as you are still technically running the train in reverse so as to use the drive train to assist with braking.

Good point, but if the wheels start going backwards Casey Jones style, you've definitely overdone it! (I know....they wouldn't....)

 

[Spamcan81]

I would think that doing this would put immense strain on the motion. Surely this would only be done in an emergency such as a runaway after all other methods had failed.

I experienced that very situation on a steam hauled narrow gauge mixed in South Africa back in 2007. A somewhat unnerving experience.

 

[d9009alycidon]

On August 1957 Britannia class No. 70012 was hauling a train from Liverpool Street to Norwich and the pin holding the loco to the tender failed near Ilford, the train came to a stand but the loco kept going with no way of stopping it until the crew put the loco in reverse and succeeded in bringing it to a halt.

 

[Merle Haggard]

Now I'm trying to visualise this and I'm not sure, but...
When a loco is running forwards in reverse gear, air is being compressed in the cylinders and then the valve (which in normal running would be the inlet one) to the regulator opens and that compressed air feeds back into the boiler, against the steam pressure which is where the retardation is provided. But I think that the next valve event would be opening the exhaust valve (which would, if the engine was running with the gear in the running direction, exhaust the steam up the blast-pipe) and the movement of the piston then draws in air through the blast pipe. If I'm right, that means that, as well as air, grit and ash in the smokebox also gets drawn into the cylinders, which would greatly increase bore and ring wear. Though probably a price worth paying if the alternative is a collision.

As an aside, I remember dead steam locos with all their motion on being moved around sheds and occasionally out on the main line going for scrap and the sound of air being compressed and then released was very loud! (and the loco doing the moving would be really working hard).

 

[Magdalia]

It is important to remember that wheels are rotating at a variable number of revolutions per second, but celluloid film had a fixed number of frames per second. At some speeds what is captured on celluloid film can give the optical illusion of backwards rotation even though the actual rotation is forwards.

 

[edwin_m]

It is important to remember that wheels are rotating at a variable number of revolutions per second, but celluloid film had a fixed number of frames per second. At some speeds what is captured on celluloid film can give the optical illusion of backwards rotation even though the actual rotation is forwards.

That often happens with spoked wheels, but I think it's unlikely to happen with the connecting and coupling rods of a steam locomotive.

 

[Dave W]

I suppose this is somewhat akin to dynamic braking on trains with electric motor drives, as you are still technically running the train in reverse so as to use the drive train to assist with braking.

Interestingly I was reading a report into the overrun at Guildford in 1953 recently where a "converted" motorman tried to reverse his unit in an emergency, probably out of habit from his steam days:

Thus, when the emergency arose he reverted to an old time locomotive practice and tried to reverse his motors. This practice, although it may at times assist the deceleration of steam trains, generally does little more than trip the overload relays of electric trains and allow them to coast freely.

I'm not an expert in this field but I think I'm reading right that he was relying on the electro-pneumatic brake which lost effectiveness when the relays overloaded. Q

Accident at Guildford on 18th September 1953 :: The Railways Archive

Archive of UK railways documents

www.railwaysarchive.co.uk

 

[341o2]

Brian Fawcett recalled an incident on the Central Railway of Peru in the days before continuous brakes, where the crew decided to "join the birdies" (or jump) regarding a runaway train, with the engine in reverse. pp204/5 of the Plateway Press reprint

They set off on foot for the next station, only to hear a train coming, which was the one they had jumped off. now running in reverse, the easing of the grade, plus the sand drag had stopped it. Engine brakes were off, because the loco was in reverse.
So they boarded the train, and kept quiet. However, flats and and slack car tyres were noted, Attempts by the train crew to explain raised official suspicion.
Eventually, one of the brakemen confessed. The story seemed improbable, but the evidence overwhelming, and then came the irony of being disciplined for needlessly jumping off their train. Had the sand drag failed to stop the runaway train, and it had smacked into the cliff at the end of the sand drag, there would have been no disciplinary action

 

[edwin_m]

Rolt in "Red for Danger" recounts an accident at Braydown on the Somerset and Dorset, where a driver engaged in shunting saw a train approaching on his line and its crew jumping from the footplate. He opened the regulator in reverse to mitigate the collision, then realised the other train was now slow enough that he could jump from his own train, board it and bring it to a halt. Collision averted, but his fireman had also jumped, and the original train ran away several miles, demolishing Midford station and most of the wagons, before very fortunately derailing before it got to the dead end at Bath Green Park.

 

[Irascible]

I would think that doing this would put immense strain on the motion. Surely this would only be done in an emergency such as a runaway after all other methods had failed.

You can put enough stress in the motion to slip the wheels going forwards, it's not any more force. If you keep the regulator completely shut there might be some interesting pressure changes in the pipework, but I guess that's why you'd open the draincocks too ( as well as the normal reason ).

 

[Sir Felix Pole]

The Union forces chasing Buster Keaton and Marion Mack in the legendary film 'The General' (1926) demonstrate the technique (54:40 onwards).

The General

As an aside, Buster Keaton was a noted railway enthusiast and got rather carried away in making the film. It went way over budget and received poor reviews initially, meaning he lost his independence as a producer from which he never really recovered. It is now regarded as one of the greatest films of the silent era.