Locomotive Management including Cylinder Cocks

Is it rare? I have film of all of them slipping. But at the end of the day, those of us who are not drivers or fireman on the main line can't really question the way an engine is driven in any particular circumstance.

 

At the end of the day large steam locomotives are always prone to slipping when getting away from a stand. Pacific's are always going to be worse than 4-6-0's obviously. Worse if the loco is cold, and the cylinder taps are blowing oily water onto the rails. Much better on a mid run stop on a sunny day, when the tyres have been cleaned up with some reasonable braking. I defy anybody to get a pacific out of Plymouth Eastbound without her losing her feet once or twice. (and there is plenty of evidence of me trying, and failing miserably, on youtube). The important thing is to be ready and waiting for a slip, and to react very quickly before it gets out of hand.
There are also some places where locos always seem to want to slip. As you enter Whiteball tunnel they often have a little dance, fine if you are expecting it. There is also a greaser towards the top of Dainton which is always ready to catch the unwary. Despite the opinion of the producers of 'Casey Jones' I do not consider that a slip is compulsory when starting away. I will leave those of you who are much better qualified to give the definitive answer. TTFN A

 

Well said Andy and a Happy New Year to you.

 

Not EVERY station! Basingstoke going south was a very hard restart. Slight curve on an up grade, but more because it always seemed to have a build up of grime etc on the track from the number of steam locos that stopped there. Leaking oil from flat tops I expect! So it always seemed to look very slippery.

Winchester South on the downgrade could also see some slips. But mainly when the loco crew were going for the record to passing Shawford from the restart. Can't remember what that ended up as and who held it. But there were some very, very noisy restarts there accompanied some times by a slip or two as a lot of throttle and a lot of cut off was used to get into speed as fast as possible. Never did that bit on the footplate, (or I think so), so didn't see it first hand up front.

 

Think you will find the report squarely pointed the finger at the driver, for not locking the reverser on the exit from Durham, if it had been locked, it would not have been able to spin into mid gear, carry over water, with the obvious catastrophic events.

It is mentioned in a NELPG news, that is available on-line, if I get the time I will post a link, however this incident has been done to death already, a forum search will help...

 

Has anyone actually answered MellishR's question? I appreciate all the information from those who know what they are talking about and find it interesting, but the question was about the length of time that steam was coming from the drain cocks before the loco moved off.

Is it warming up the cylinders, clearing out the cobwebs, a cry for attention......? ;-)

 

There are any number of reasons why the train may not have moved as soon as the cocks were opened. I can't recall the particular arrangement for no. 19 but certainly some of the other A4s have the drain cocks operated from the fireman's side. It may be that the person sitting in the fireman's seat opened the drain cocks in readiness for the regulator to be opened or it could be that there was a delay between the moment the guard unfurled his flag and it being waved above his head (or if there are RA indicators at Peterboro this might have contributed to the slight delay). It is also possible that the loco simply did not want to move when the regulator was opened - it happens even with Gresley's finest on occasion! Certainly having the cylinder drains open prior to departure is unlikely to have any detrimental affect on the locomotive's operation.

FWIW I'm not entirely comfortable with the almost forensic study of the minutiae of locomotive operation particularly when it is directed at specific events.

 

Hey it could be worse, could have been a certain black 5, the drain cocks on that are under the control of some third party existential being.

 

No, we know who it is: it's Mr Broken Valve ring trying to escape by that route!

Generally, a standing loco would have the taps open all the time to prevent any build up of steam within the valve chest and cylinders possibly causing the engine to move off on its own, if left in fore or back gear, a not-unknown and very worrying occurrence. The steam could come from a few places depending on the class of loco, but the most obvious source is a slight, and sometimes not so slight, leakage past the regulator valve. Different types of valve are more prone to leakage than others, but some leakage is common.

 

Isn't the answer much the same as the answer why said locomotives are much cleaner and better maintained externally than they were back then?

 

First, sorry to have caused so much excitement through what I believed to be an innocent question, and certainly not intended to cast the slightest doubt on the competence of the driver or anyone else.

The nearest I've seen to an answer is in (what is now, in this split-off thread) post 29. I would expect a slight leakage of steam past the regulator to produce only a wisp of steam from one or more of the drain cocks, depending on the positions of the piston valves. Clouds of steam imply a significant opening of the regulator. Normally when the regulator is opened the train starts to move. On that occasion it didn't, for about 30 seconds. It could be that the brakes were slow to release, and I was wondering whether anyone could confirm that. Otherwise

I'll settle for that explanation, unless anyone has a better one.

I don't think anyone has suggested that it could.

Only curiosity about what seemed to me an unusual occurrence.

 

I refer you to my day to Eastbourne in December, Tangmere slipped more than 40 occasions during the day, conservatively... In these videos you can catch at least 7... 4 of them on the Balcombe tunnel start..

http://www.national-preservation.com/threads/rtc-christmas-sussex-belle.391386/page-3#post-1021293

 

IIRC the reverser spun into full forward gear. Ray.

 

Don't you believe it, mate! Many an engine has wandered off with the regulator closed simply due to the steam leaking past it. There has been many an accident, and I was almost a statistic to prove it.

1970, and I was a fireman on an Ivatt Class 2 on six bogies. It was ecs, fortunately, as it was a driver training run with a trainee and instructor driver. Approaching the terminus, the trainee braked the train as usual to a halt, and I got down and went between to unhook. I had barely got between when a mate on the platform screamed at me to get out. I'd no sooner extricated myself when the train pulled away, but after a few yards there was a big bang as all the brakes came on. How?

The trainee had brought the train into the station with the reverser in the drift position and the regulator shut. After he'd stopped, he pushed the brake lever back to OFF, but touched nothing else, so the small ejector was slowly making vacuum. It took about the same time to blow the brakes off as it did me to get down and go between, and in that time, steam passing the closed regulator had built up sufficient pressure in the valve chests and cylinders to move the engine and six coaches - all in a mater of seconds.

I don't know if a regulator blowing through had anything to do with the occasion your quoting, but a blowing regulator can produce far more than '...only a wisp of steam.'

 

We had an engine on the Strathspey that, for a short period, to get a train moving (6-7 Mk 1s normally) all the driver had to do was close the cylinder draincocks.

 

I've given the facts on the incident, as told to me by the NELPG rep on the footplate, on Nat Pres on several occasions. Yes, the reverser wasn't locked. The handle spun wildly when the slipping started. It hit the drivers arm quite heavily. He did nothing to shut the regulator. It was eventually shut by the NELPG rep but, by then the damage was done and the slip had virtually ended.
With regard to Bittern's departure from Peterborough, it's pure conjecture but the driver gets the RA, moves the brake to off and opens the reg slightly. However, the train brake is still coming off so there is significant resistance to motion. As the brake comes off, the loco overcomes the resistance and sets off. There is a flaw in that, of course, as the train was most likely held on the straight air brake, rather than the train brake. Another one is that the guard tailed him; we don't get to see the drivers actions. Yet another is that the cocks were opened at the point where steam is first seen being issued and that first flush was the steam chest being emptied. Yet another possibility is that the cocks were already opened and the act of moving the reverser into forward gear emptied the steam chest. There are lots of possibilities. It's all conjecture, though! Only those on the footplate will know what happened.

 

I did say "a slight leakage". The situation at Peterborough that interested me was with the drain cocks open, a lot of steam coming through, and yet the train not moving. I can of course understand that with the drain cocks closed and the brakes off even a slight leak past the regulator could build up enough pressure in the cylinders to start a train moving. Dave Goulder's song "I'm the man who put the engine in the chip shop" tells of one such event.