Starting away with steam loco

Hi all.

What is the general process when starting away with a steam loco? Full forward 75% cutoff and then feather the regulator for the first few valve cycles then shut drain cocks and alter reverser down to around 50%?

Obviously this will depend on light engine, gradient, class of loco, etc. but any general explanation much appreciated.

Cheers

 

I'm an expert. I've driven several steam locos in Train Sims

Large ejector open to create vacuum to release the brakes, small ejector open after this to maintain vacuum, then it is as you say, though I suspect full forward gear would not always be needed; it would depend on load, gradient etc as you allude to. Then carefully open regulator and wind back the cut off.

Theory suggests the most economical way to run is full regulator and short cut off, but I understand some loco types didn't respond well to this, so tended to be driven with higher cut off and the regulator used to control the speed.

Now I await the proper answer from one of those on here with real knowledge

 

Again, a long way from an expert but agree it depended on many factors, including the engine. A Stanier Pacific, for instance, generally started at 40% cut-off to reduce the likelihood of a violent slip. If she didn't move with that, close the regulator, drop down to 55% and try again, at which point something was almost guaranteed to happen (John Powell in The LMS Duchesses, edited by Douglas Dougherty (1973) MAP Ltd, Kings Langley, ISBN 0 85242 325X Page 40. He points to an adhesion factor of only 3.73 and a very large forty element superheater containing a large mass of steam still to go through the cylinders after the regulator was closed.

The full regulator theory works alright on multi-cylinder engines but those with two outside cylinders tend to disapprove, especially when getting a bit run down. Realistically, you wouldn't drop one of these below about 30%.

 

So you’re not bothered about enjoying yourself, then?

 

Certainly! You're very welcome to it!

 

That's all well and good, but you've missed the solid ten minutes of work by the fireman before the flag is even waved. Ignore that and the driver can do all the 75% stuff he likes, but he may well be coming to an ignominious halt just round the corner

Tom

 

Ahh, but the locos I've driven have the option of auto-firing. Haven't you found the switch to turn this on yet?

 

I prefer the one to turn it off!

Before you ask, yes, I have driven 47s. The job satisfaction level in simply moving the handle around was zero, on a par with pressing the buttons on a lift to reach the right floor.

 

A 51xx or 28xx will generally start quite happily in 45% cut off and a fair amount of regulator (19 times out of 20). If it won't go then drop the lever down a notch. I can't think of a properley set up loco which needs the full 75% to start.

 

40% was normal to start a Stanier Pacific; drop it another 15% if she didn't move first time.