Steam Engine stalls?

[Gilbert]

I was told on Saturday about a steam loco that had "wheel slipped and stalled". It did not get going again until a diesel helper arrived and attached to rear of train.

What would actually cause that? The train was on a bank and was about 11 coaches so gradient and load related no doubt but what happens in a "stall"?

Chris H

[LMS2968]

A stall, quite simply, is when a loco comes to an involuntary stand and is unable to  restart its train and move forward. It can be caused by a lack of adhesion between steel tyres on steel rails when conditions are poor, but other reasons can include shortage of steam, forcing the train to stop for a 'blow up'.

 

If you can keep the train moving, even slowly, in poor adhesion conditions, this is easier than restarting once the stall has happened.

[Gilbert]

3 minutes ago, LMS2968 said:

If you can keep the train moving, even slowly, in poor adhesion conditions, this is easier than restarting once the stall has happened.

Thanks - there was a period of very slow running prior to the final stall....

[Jeremy Cumberland]

A stall is when the train comes to a stand (for any reason) and the locomotive can't get it moving again.

 

There are two types of stall. One is where the locomotive does not have the tractive effort to move the train. This typically involves a two-cylinder locomotive with one piston at dead centre, and therefore not doing any work. If steam pressure x piston area of the other cylinder multiplied by crank throw divided by wheel radius is less than the force required to move the train, then the train will not move. In this situation, it is quite likely that the locomotive can be moved in the other direction (perhaps compressing the couplings between the leading vehicles), and after reversing a short distance the locomotive will then be able to draw the train forward.

 

The situation you were told about involves wheel/rail adhesion. The force required to move the train is more than can be transmitted between the wheel and the rail. Problems are common in the autumn with leaf fall, and a small amount of water on the rail makes a nice lubricating paste (heavy rain tends to wash the greasy debris from the rail surface, and usually improves adhesion). Adhesion is considerably improved by using sand, but I imagine that sand was being used when the train slipped to a stand. It is also possible to apply sand manually. This is something I was doing yesterday - we had problems with slipping on the railway I volunteer on, and all trains carry sand in plastic squash bottles with a hole in the cap to act as a dispenser, but it is one thing walking along the track on a single track  heritage railway and something else on a main line, and quite likely there was no safe means of manually applying sand.

[Wickham Green too]

Now I thought this topic was going to be about the bays in a roundhouse which are sometimes called 'stalls' but ...........

 

Yes coefficient of friction is greater when moving than when stationary ...........................

[Edwin_m]

2 hours ago, Wickham Green too said:

Yes coefficient of friction is greater when moving than when stationary ...........................

For the purposes of this discussion, surely the other way round?  Once the wheels start spinning, there is relative motion between the wheels and rails, and the coefficient of friction reduces.  

 

For completeness, modern locomotives make use of the fact that friction increases when there is a small amount of relative motion, but it needs an automatic "creep control" system to keep the wheel within this speed range and avoid an increase in relative speed that would cause adhesion to reduce.  

[kevinlms]

4 minutes ago, Edwin_m said:

For the purposes of this discussion, surely the other way round?  Once the wheels start spinning, there is relative motion between the wheels and rails, and the coefficient of friction reduces.  

 

For completeness, modern locomotives make use of the fact that friction increases when there is a small amount of relative motion, but it needs an automatic "creep control" system to keep the wheel within this speed range and avoid an increase in relative speed that would cause adhesion to reduce.  

But my understanding is that 'creep control', is only slightly above the speed of the loco, but slipping on a steam loco is significant and can cause some damage to the motion.

[Jeremy Cumberland]

17 minutes ago, Edwin_m said:

For the purposes of this discussion, surely the other way round?  Once the wheels start spinning, there is relative motion between the wheels and rails, and the coefficient of friction reduces.  

 

For completeness, modern locomotives make use of the fact that friction increases when there is a small amount of relative motion, but it needs an automatic "creep control" system to keep the wheel within this speed range and avoid an increase in relative speed that would cause adhesion to reduce.  

You are right, but I think there might be confusion over two things.

 

The friction between two objects that are not moving relative to each other is higher than the friction between two objects that are moving relative to each other. This is familiar to almost everyone: it is more difficult to get something to start to move than it is to keep it moving. This additional friction between non-moving objects is sometimes called "stiction" (static friction or stick-friction).

 

In the context of a stalled train, stiction mainly affects the axleboxes down the train. Once a train has stopped, it requires more force to get it moving than was needed to keep it moving at very slow speed. This in itself means that if a locomotive has slipped to a stand because of poor adhesion, then you generally need to engineer a significant increase in adhesion to get the train moving again (which it might be possible to do with manual sanding). However, if the original wheelslip was due to too much force being applied to the locomotive wheels - more than could be transmitted to the rails - then simply applying a lower force (cracking the regulator open, perhaps) might be enough to restart the train.

 

Stiction also comes into play with the wheels slipping in the first place, and locomotives recovering from a wheelslip. If the wheels aren't slipping, you can transmit a considerable force between a locomotive wheel and the rail. This is reduced by oil deposits, fallen leaves, a thin film of water from drizzle or dew, ice, caterpillars and any number of other things, and it is increased by things like sand, but in all cases, once the wheels start to slip, the friction (and the force that can be transmitted) reduces to very nearly nothing. The first thing to do when slipping is to re-synchronise the speed of the wheels with the speed of the train, and in a steam locomotive, this means closing the regulator. Once the wheels have stopped slipping, you can then gently apply more force to keep the train moving, but not too much else you'll slip again.

 

35 minutes ago, kevinlms said:

But my understanding is that 'creep control', is only slightly above the speed of the loco, but slipping on a steam loco is significant and can cause some damage to the motion.

Exactly right. Creep control tries to detect the smallest discrepancy, because this gives the fastest recovery, re-synchronising the speed of the wheels with the speed of the train. Ideally, a steam locomotive driver will do exactly the same thing, but he is rather limited in his options. Ideally, he would close the regulator to the exact amount needed to apply the correct force at that speed, but in practice he usually has to close the regulator fully and then re-open it, during which the train will have slowed down. If the driver does not close the regulator quickly enough, then the motion can be damaged, and I expect most of us know of the incident involving 60532 Blue Peter, but drivers having difficulty controlling wheelspin isn't confined to steam locomotives, although usually it results in damage to rails and wheels rather than the rest of the locomotive.

[Hal Nail]

Its not that uncommon for trains to stall on the Midhants and, regardless of the weather or rail conditions, it seems it is normal practice to attribute it to the person firing!

[woodenhead]

1 hour ago, kevinlms said:

But my understanding is that 'creep control', is only slightly above the speed of the loco, but slipping on a steam loco is significant and can cause some damage to the motion.

And to the track if the driver fails to arrest the motion, there was an incident I think in Scotland that there was video of, the locomotive spun so fast it literally heated the rails to melting point leaving dents in the rail where the wheels had been.

 

For your delectation of wheel slipping watch this 13 minutes of pain from South Africa trying to start a coal train

 

Did find the occasion Blue Peter lost it, a lot of damage to the loco and the driver too was injured.

 

Edited October 23, 2023 by woodenhead

[keefer]

15 minutes ago, woodenhead said:

And to the track if the driver fails to arrest the motion, there was an incident I think in Scotland that there was video of, the locomotive spun so fast it literally heated the rails to melting point leaving dents in the rail where the wheels had been

I don't know if you meant a steam loco but ISTR a Western hydraulic on a railtour (at North Queensferry perhaps?) where the driver was seemingly unaware that wheelslip had started, so just applied more power hence damaging the tyres and rails.

[woodenhead]

9 minutes ago, keefer said:

I don't know if you meant a steam loco but ISTR a Western hydraulic on a railtour (at North Queensferry perhaps?) where the driver was seemingly unaware that wheelslip had started, so just applied more power hence damaging the tyres and rails.

That's the one - no wonder I couldn't find it.

 

[ColinK]

I was on that Western trip, sad the way it ended.

[doilum]

This might explain one of the most bizarre railway incidents I have ever witnessed. Before we were married (1979) my future in laws lived with a great view of the railway through Castleford. One Saturday afternoon as I arrived I noticed a class25 with the west bound Newcastle to Manchester newspaper train returning empty. It was held at the signal directly behind the rugby ground. When I came to leave about half an hour later it was still there. What caught my eye was that the Wheldale colliery shunter had been fired up and was on the main line heading east. A few minutes later it had negotiated the cross over and was closing on on the rear of the train. With an exchange of horn blasts the shunter applied a hard bump start and with a cloud of diesel exhaust the 25 was on its way. The shunter returned the way it came and all involved probably declared the fifth.

.

[roythebus1]

Wasn't there a more recent incident with Tornado wheelslip at Durham, motion was badly damaged when it reportedly got to 140mph whilst not moving and the driver broke his wrists trying to move the reverser.

[Jeremy Cumberland]

5 hours ago, woodenhead said:

For your delectation of wheel slipping watch this 13 minutes of pain from South Africa trying to start a coal train

 

I reckon the driver managed it very well, apart from his lack of foresight in not having any sand. He clearly understood not only the behaviour of his locomotive and the rail adhesion, but also the resistance of his train (sometimes getting it to roll back before trying to move it forwards) and, quite possibly (although we cannot clearly see it) the assistance he might get from the buffers and couplings of the leading wagons. By all means argue that he should have got some sand (or an assisting locomotive) but perhaps there was neither to be had.

 

Every time he slipped he sought to control it immediately, most of the time by partially rather than fully closing the regulator (although this was not always successsful), and when he did apply steam, it was very gently, as you can see several times where an increasing amount of steam emerges from the glands over several seconds before the locomotive slips. Unfortunately, the regulator is a long way from the cylinders, and superheating makes it even harder for the driver to control what is actually happening in the cylinders. It looked to me that the driver opened the regulator to a position he thought might work, and left it there, waiting for the steam chest pressure to build.

[Cruachan]

1 hour ago, roythebus1 said:

Wasn't there a more recent incident with Tornado wheelslip at Durham, motion was badly damaged when it reportedly got to 140mph whilst not moving and the driver broke his wrists trying to move the reverser.

That was 'Blue Peter' in 1994, as per the video shared in an earlier post.

[Cruachan]

5 hours ago, ColinK said:

I was on that Western trip, sad the way it ended.

The locomotive's owners, the Diesel Traction Group, appear to describe that trip in fairly glowing terms:

Quote

http://www.westernchampion.co.uk/loco-d1015-railtour-archive-2008.php

The Western Chieftain (Pathfinder)

Friday 19th - Sunday 21st June 2009

The stop at Perth revealed that we had a coolant leak on the leading engine but the engineers were confident it wouldn't be a problem. However things got worse as we headed towards Edinburgh and the engine was shut down to try and effect a repair. As the passengers sat back and enjoyed the view from the world famous Forth Bridge, it was anything but relaxed in the engine room as DTG Engineers, Williams and Vial, attempted to sort out the coolant leak.

Departure from Edinburgh saw the loco only a few minutes late and back on two engines, a successful repair having been carried out with minimum disruption and few on the train realising that anything was amiss. The remainder of the journey South was without mishap and the train was back on time by Preston. As 66206 relieved D1015 at New Street the job was done and D1015's most ambitious tour had proved to be a massive success.

More than a few have declared this tour the best one that they have ever travelled on and on reflection they may very well be right!

Edited October 23, 2023 by Cruachan

[pH]

7 hours ago, woodenhead said:

And to the track if the driver fails to arrest the motion, there was an incident I think in Scotland that there was video of, the locomotive spun so fast it literally heated the rails to melting point leaving dents in the rail where the wheels had been.

 

7 hours ago, keefer said:

I don't know if you meant a steam loco but ISTR a Western hydraulic on a railtour (at North Queensferry perhaps?) where the driver was seemingly unaware that wheelslip had started, so just applied more power hence damaging the tyres and rails.

Derek Cross told of a Polmadie Duchess on a down sleeper via the G&SWR line that slipped starting away from Kilmarnock. The driver couldn’t get the regulator closed and the engine slipped for several minutes, burning through to the web of the rails.

[5944]

It seems it was a combination of the load (12 Mk1s), the route (on a curve and a gradient) and the presence of a flange lubricator that caused the slip and the inability to restart the train. There's a few flange lubricators on the network that cause problems for steam that don't affect other traction. 

[keefer]

The line from Inverkeithing up to N. Queensferry is 1 in 70, with a tunnel which ends just before NQ station.

There was a derailment in 1954 caused by a loco slipping back in the tunnel without the driver realising it - the 13-coach train ran back through catch points (on the Inverkeithing side of the tunnel).

The last 3 coaches derailed, one of them foul of the Down line but there was only one recorded injury. The line here is also on a high embankment and it is only due to good fortune that there weren't more casualties.

https://www.railwaysarchive.co.uk/docsummary.php?docID=982

 

Para.27 of the Report is interesting in that records showed that between 1/1/52 and 7/3/54, 30 trains had "failed to negotiate the 'Forth Bridge Incline' ." - 12 of these (2 pass + 10 freight) were at NQ tunnel. In most cases, an assisting loco was sent from Inverkeithing.

Mention is also made of the fitting of tunnel wall lights to assist drivers, referencing previous similar accidents at Glasgow QS (1928) and KX (1945)

 

Edited October 23, 2023 by keefer

[faulcon1]

But what I'd like to know is who pays for the damage caused either to a loco and or permanent way. In Blue Peter's case the then BR should have paid for the total cost of the damage but I've read in other places that the owner Geoff Drury paid for the majority of the damage with BR paying a token amount which is very wrong. The powers that be sanctioned the locomotive to run on the line and the crew to crew it and they damaged it so the powers that be are responsible for the total cost of rectifying all the damage caused, NOT the owner of the locomotive. The same with the Western for it wasn't the locomotive owners fault that the engine slipped but the man who was driving it and so who paid for the damage caused to the permanent way and any damage to the Western. Don't for get if a loco causes delays to other trains on the line the operators are very quick to point the finger at the locomotive's owner and demand compensation for delayed services so the gate has to swing both ways.   

[roythebus1]

Surely it's the locomotive's insurers who will pay for damage to other people's property?

[The Stationmaster]

7 hours ago, faulcon1 said:

But what I'd like to know is who pays for the damage caused either to a loco and or permanent way. In Blue Peter's case the then BR should have paid for the total cost of the damage but I've read in other places that the owner Geoff Drury paid for the majority of the damage with BR paying a token amount which is very wrong. The powers that be sanctioned the locomotive to run on the line and the crew to crew it and they damaged it so the powers that be are responsible for the total cost of rectifying all the damage caused, NOT the owner of the locomotive. The same with the Western for it wasn't the locomotive owners fault that the engine slipped but the man who was driving it and so who paid for the damage caused to the permanent way and any damage to the Western. Don't for get if a loco causes delays to other trains on the line the operators are very quick to point the finger at the locomotive's owner and demand compensation for delayed services so the gate has to swing both ways.   

A very complex area but don't forget that delay compensation paid in respect of  trains hauled by 'historic traction is capped so they never pay the full extent if they cause serious delays (unless the cap has been removed but I doubt that?).

 

And equally nowadays all private locos running on the national network are accompanied by an owner's representative who is supposed to be familiar with the working of the loco.  Always very difficult to 'interfere' on the footplate but the rep should be on the lookout for potential problems.  But deciding liability will always  be a very mixed thing with numerous factors to take into account.  effectively in every situation there are at least three parties involved although the infrastructure owner's position can usually be confirmed one way or the other by what has happened to other trains using the route prior to a problem involving a special, particularly adhesion troubles.

 

But as ever when something starts to go wrong, such as serious slipping when trying to start away the perpetual problem is knowing when to give up and shout for assistance.

[Jeremy Cumberland]

There are a variety of causes. We recently had 35018 British India Line stall at Dalton Bank on the Cumbrian Coast line. Not particularly surprising in the leaf fall season and with the weather at the time - there had been adhesion problems on the Ravenglass and Eskdale Railway earlier that day. As far as I am aware, the locomotive crew acted in the best manner possible and no damage was caused, but the train was stuck there for over two hours awaiting assistance from Carnforth, with service trains being delayed as a result.

 

Who is to blame for the delay to other trains? Not the locomotive owners or the train crew, that I can see. Network Rail, perhaps, for not maintaining suitable railhead conditions, but the usual class 156s seemed to manage just fine. The schedulers for allowing such a train to run at dusk in late October, where there is always a risk of dew and leaves creating a horrible slippery coating on the railhead? Quite possibly. Or perhaps it should be the train operator for not attaching the usual diesel on the rear or the line operator (I don't know who is responsible here) for not insisting on it.

 

To my mind, the decision to run such a train at such a time of day/time of year without a second locomotive attached is dubious, but I expect the company most at risk from the decision - Northern Trains - had no say in the matter.

 

Even some of the well-known examples where damage was caused and blaming the driver might seem obvious, I am not entirely sure it is so clear cut. Blue Peter's famous wheelslip came unexpectedly, and if the locomotive primed (always a risk with wheelslip), then it might be very difficult to shut the regulator. Western Champion at North Queensferry seems in large part due to the driver not being familiar enough with the traction to understand what was going on, but who appointed the driver to this duty? Certainly with Western Champion, it is hard to attach any blame to the locomotive owners unless it was they who appointed the driver, so I can't see why it should be their insurers who had to pick up the bill for damage to the track.

Edited November 10, 2023 by Jeremy Cumberland