Steam & Excursion > UP 3985 Backhead Question

I picked up a July 1989 copy of Trains Magazine. It features 3985, with a terrific article of running 3985 in regular service. Page 32-33 has a photo spread the "Nerve Center" that identifies all of the valve knobs, and levers.

What is:
"Emergency Steam Valve" On the engineer side with a distinct triangular knob.

"Try cocks (3)" (I thought it should be tri cocks) But what are they for? On engineer side near throttle.

"Water regulator valve" On fireman side next to cab wall but looks like attached to backhead on a bracket.

"Spill Light" Just above the water regulator valve. (At this point 3985 was still coal fired)

TIA Tom

Emergency steam valve is for the power reverse. If all the air is gone and you have to use it, this will change it over to steam operation, but only for a couple times since the steam will destroy the packing cups.

Tri cocks are a backup to the water glass for determining the level of water in the boiler. If you crack the top one open, you should get steam. The middle and lower one should produce water.

Water regulator valve is for the feedwater heater. It determines how much water is pumped through.

Spill light is an indicator for the FWH that tells you when to pull the valve open to start feeding water.



Edited 1 time(s). Last edit at 12/18/11 13:58 by Frisco1522.

OK
1. Emergency steam valve is a valve on the engineers side, triangular shaped to identify it from other valves. It is an emergency use valve to allow steam to operate the reverse gear which would be a one time use as it would destroy the gaskets used for the pneumatic use of the gear. It is a triangular valve and painted yellow separate and apart from the other red handled valves to distinguish it.

2. The three try cocks, tri cocks, are for testing the water levels in the boiler to see if the water glass is reading properly. Sometimes the water glasses, if not blown down properly, could give a false water level reading.

3. The water regulator valve is the firemans valve for putting water in the boiler. On the 3985 there is the priming handle which when pulled part way puts steam to the water pump and activates it sending water from the tender forward and when snapped all the way back puts steam into the water delivery to override the check valves in the boiler. The regulator valve with the sign controls the amount of water flow sent by the water pump.

4. The spill light was for use by the fireman to let him know when the water delivery to the boiler dropped and the check valves closed and started dumping water on the right of way.

I hope these answer your questions. I spent a number of hours in those seats operating them. Jack, all this sound good to you?

Bob Krieger
Cheyenne, WY

Hey Mr. Booster, looks like we both took this one on at the same time. 844 has te FWH and 3985 ispirates direct to the boiler.

Bob Krieger
Cheyenne, WY

There you go Tom, TO gift certificates would be a nice Christmas present to Don and I, hahaa.

Bob Krieger
Cheyenne, WY

You're right Bob, shoulda remembered that from my firing days on the 3985. Getting senile I guess.

Bob has everything correct. To clarify the different feedwater systems between 844 and 3985:

844 has the Worthington S type, i.e. steam driven high pressure piston pump to supply heated feedwater past the top mounted boiler check valve, and into the boiler.

3985 has the Elesco Exhaust Steam Injector, which mixes exhaust steam with the feedwater. If the exhaust steam is not sufficient, the change-over valve in the Elesco Injector moves and then supplies "live steam" from the boiler, in order to preheat the feedwater. Thus, the Elesco system can be used with the throttle closed (drifting down hill) or even at standstill (on display). The Worthington system pumps virtually stone cold water if the throttle is not open, i.e. no exhaust steam.

WOW! Talk about right from the source. Thank you guys for the most excellent explanations. And gee, There is Bob's picture just 2 pages prior to that photo spread of the "Nerve Center of 3985". In the July '89 Trains mag, Bob is leaning out the fireman's window. "CLEAN STACK makes fireman Bob Krieger happy as 3985 rolls east out of Laramie, Wyo."

Thank you folks. Tom

Bob3985 Wrote:
-------------------------------------------------------
> OK
> 1. Emergency steam valve is a valve on the
> engineers side, triangular shaped to identify it
> from other valves. It is an emergency use valve to
> allow steam to operate the reverse gear which
> would be a one time use as it would destroy the
> gaskets used for the pneumatic use of the gear. It
> is a triangular valve and painted yellow separate
> and apart from the other red handled valves to
> distinguish it.
>

Many years ago, there was an essay in TRAINS written by an engineer who was wyeing an SP cab-forward at Cascade Lake, Oregon in the depth of winter and at night. The wye had recently been cleared leaving a snow channel of several feet on either side of the track. His fireman had dropped down to turn a switch where space was available in the snow channel. Somehow there was an immediate loss of air pressure (IRC, piping was torn off by ice). As the locomotive passed the switch, the hogger had to think quickly as the end of track approached. For his own safety, the fireman remain on the ground as the locomotive passed. Recalling the emergency steam valve for the power reverse, the engineer began searching for it. Because of lack of use, this valve was often very hard to turn. Additionally, a new shop crew member would, sometimes, erroneously paint the valve red. Fortunately in this story, the valve was painted yellow facilitating the engineer's search in the dark and the valve turned. While the locomotive did hit the snow bank at the end of track, it only had damage to the cab-forward's pilot. After hearing the full story and happy to hear the engineers quick action of the emergency valve, the road forman ensured the damage, and any related demerits, would quietly disappear from any reporting.

Power reverse (Reserve Air) pressure alternatives...

The old ICC Steam Loco Rules stated only that an alternative means must be provided to operate the power reverse, in cases of lost system air pressure. They permitted EITHER a live steam (reserve) source OR a separate(d) compressed air storage tank to power the reverse gear. The rules stated that the reserve air supply tank must have a 'check valve' in the air supply pipe to the reverse gear's cylinder --- to prevent operating pressure being lost due to a major failure of the locomotive's main air supply system.

Many PRR locos were fitted with this tank attached to the rear of the power reverse cylinder, clearly visible under the engineer's running board.
Many other roads used the separated air reservoir alternative for economy reasons and to avoid the ruining of the packing cups of the power reverse and to avoid the dangerous searching for the change-over valve (as sighted, above). The spare air supply was instantaneously available under any emergency condition.

The use of the steam change-over valve system (and its permissive wording in the steam loco inspection law) ought to have been eliminated---years ago.
It is a dangerous and an unsuitable anachronism that should never be used in today's steam loco service.
The use of the check-valve protected, compressed (spare) air, storage supply should be the only approved back-up method for powering these reverses! (Or more modern, fail-safe pressure retention schemes or systems....).
IMHO!

Overfire Jets

NEW!

And another shortcoming of a steam 'emergency' power source (power reverses....), cont'd.

A true problem with little used steam-fed lines: They soon fill up with standing condensate.
So, over years of non-use, when most needed, the operation of the steam line to the power reverse injects the power reverse cylinder with rusty, filthy skanky water!

Water in such a space is a hazard and it would take multiple, full stroke, cyclings of the power reverse's piston to actually get steam to the cylinder. Also, water, unlike compressed air, is NOT compressible; there being no 'cylinder cocks' on the power reverse, it would truly be a 'one-time' use system.

The employment of the reverse gear for stopping is useful only for light-engine moves! If the air system fails while hauling a train, Westinghouse's 'Automatic Air Brake' would safely bring the train to a stop. In case of an sudden, outright calamity ---- Newton's Laws of Motion would rule the events!

Get rid of that improvised piping, NOW. Looks like an original 'lawyer's solution' to a rarely occurring event.

(Editor: Keep this one unacknowledged and undated, too!)

Wes.