What is the reason for the steam escaping from the cylinder area when running and thus unlikely to be blow down of tghe cylinders?
I notice peculiar coupling on the Flying Scot. It seems to be a hoop and loop.
I hope for the employee’s sake the British have changed to knuckles.
Does the steam valve ever close both ports at once? If the locomotive is in motion something would have to give!
The steam you see escaping from the bottom of the cylinders is part of the system to remove the condensate from the cylinders. Hot steam going into a cold cylinder will partially condense, and water cannot be compressed. Many times at the beginning of the locomotive’s operating day, the engineer will open the blow down cocks and open the throttle slightly to force steam through the cylinder to warm it up, thus minimizing the condensate problem. But periodically it must be repeated during the run. If you mean around the piston shaft, well, there’s no such thing as a perfect seal.
Yes, the Flying Scotsman has hook and loop couplers and I don’t think the British have converted to North American style knuckle couplers.
You can put the valve in a position where it is open in both ports, allowing the engine to coast
Right on. I belive the proper name for the valves are Cylinder cocks.
The steam from the cylinder cocks seems to be requested by film producers who think it adds a bit of drama to the passing train. These philistines don’t realize two things: First, the cylinder cocks were designed to only be used when the locomotive is starting after sitting a while and the cylinders cool off - this is to allow any condensate to escape the cylinders and thus prevent damage to the pistons and/or cylinder heads; second, if the producers thought about it a little bit, they’d realize that the machinery of a steam locomotive needs no artificial enhancement to provide the drama - the steam from the cocks often obscures the motion of the machinery.
Tom Diehl - the engineer cannot manually put the valve in a position where all the ports are open, thus allowing for drifting. Many locomotives had drifting valves that connected the ends of the cylinders through piping and thus allowed for free drifting. These valves were connected to the throttle and closed when the throttle was opened.
Old Timer
Yes, there is a poriton of the stroke where both ports are closed, it is called the compression phase, and comes between the cutoff and release phases. What it does is it keeps a little of the steam from the prior stroke in the appropriate side of the cylinder, which is compressed by the piston as it comes in, and thus provides a “cushion.” This makes the locomotive ride more smoothly and reduces wear on the running gear.
Nothing has to give, the piston merely slows down. Shortly after this, the steam which was compressed is released to the exhaust.
Sincerely,
Daniel Parks