Sorry to ask this question if it is already on here, but on most steam locomotives, there seems to be steam escaping from various places. I know easily about the cylinders letting a few wisps out if the cylinder cocks are closed, but there seem to be other places. One place is near the cab, where there always seems to be a small line of steam. What is the purpose of this?
Most likely it’s the dynamo (small steam turbine mated to a generator) that makes electricity for the loco.
Yea the steam turbine / generator / “dynamo”, and perhaps the injector exhaust (the injectors used to add water to the boiler from the tender). It may be just steam or some mixture of steam/water; it sounds like it’s a tricky procedure to get the right combination.
Note the injector exhaust below the cab, some blowoff out the low-pressure safety valve, and the inactive generator:
Now the generator is on:
And the air brake pumps also have either some adjacent exhaust or may be leaky (most of this exhaust seems to go up the main stack on the EBT locos), which you can see on the 2nd loco in this double-header:
When the locos get worn I assume everything leaks. On one of the trains I rode last summer in colorado, I ask the engineer about steam coming out from around the pistons and he said the seals were worn out. They do the repairs in the winter. The poor thing leaked so much I didnt think it make it back up the grade.
Happy railroading.
Lee S. [:D]
Don’t assume that all of the steam venting from various places on a locomotive are leaks. Sometimes there are other reasons for venting steam. From front to back, here are the places I commonly see steam venting and why:
Cylindercocks - Two on each cylinder.These are opened before starting to move the locomotive and remain open until all condensed water has been drained. Then the valves are closed and all steam is directed to the stack. They may also be opened when running if the engine has been drifting - prior to opening the throttle again. (They are also effective in preventing “mooning the train”.)
Valve rod and Cylinder rod packing - These packing glands will start to wear with time and may leak. We never touch them when hot to prevent a catastrophic accident. However, we do inspect and tighten them during the monthly boiler wash.
House valves - These drain valves are opened when the locomotive is not being used (generally in the engine house - hence the name) to drain condensate from the steam lines to each cylinder. We close them each morning after moving the locomotive out of the house.
Smoke box drain - Not all engines have one but this is useful in draining condensate from the smoke box to prevent corrosion. One wants the smoke box to be as dry as possible.
Foward boiler washout plug -I have never seen this one leak as it is tested during hydrostatic testing but it could.
Steam dome applicances -The whistle and several pressure relief valves are on the steam dome. Since the whistle is frequently operated, it is common to see a little steam wafting around it but the valve must be opened at least 30-40% to produce sound. The pressure relief valves (at least 2 - sometimes 3) vent when the boiler pressure exceeds the valve setting. On the Jupiter one valve is set at about 155 psi and the other at about 165 psi. We operate at about 145 psi so popping the 1st safety ha
not to mention that big hole in the very front that points upwards…always seems to be leaking steam…sometimes under great force…[D)]
When it is REALLY cold,outside,steam leaks from EVERYWHERE on a steam engine!
All the appliances can leak, especially as they get worn.
Other times things can appear to leak would be on shutdown. With a few exceptions, everything that was opened is closed to save pressure for starting up the next day; and everything that was closed is opened, to drain while condensation occurs overnight. This creates many paths for steam to vent.
Actually the steam is also leaking on hot days - it just isn’t a visible. That is a problem for maintenance. What you can’t see can still burn you.
dd
Thanks for your answers; they cleared up the problem.