Pressure Gauge

In the steam industry, especially involving railroad locomotives, the general rule of thumb was, a steam pressure gauge rated/graduated for DOUBLE the working boiler pressure was used. Thus, a locomotive with a 200psi "working pressure", would generally have a 400 pound gauge.

I happened to spot this photo today while looking at some old files.

It is the polished gauge on the backhead of WMSR the first day

of the 2008 season.

Ed

Nice find Dave.

Doc,

It walked through the door yesterday.  The owner threw out a price and I reached in my pocket.  I was not letting that one go. 

Hot Water,

Thank you for the reply!

Dave

The late Bill Purdie was fond of telling the tale of a Southern Ms-4 (Heavy USRA) Mikado which was freshly overhauled at Pegram Shop (Atlanta).  A Laborer was deputized to fire it up on third trick and have it ready for the pops to be set the next day.

About four AM the Laborer came into the Foreman's office with a worried look on his face.  The Foreman asked him what was wrong and he said "boss, I been firing that 48xx out there ever since midnight and I can't get a pound of steam on it."  The Foreman thought "Uh Oh . . ."

He went out to the engine which was oozing steam from every pore and got up and looked at the steam gauge which read zero.  He checked the valve, and what do you know - they hadn't turned the gauge on.  He turned it on and it went up to 400 Pounds - the engine was supposed to steam at 200.  He told the Laborer to put the fire in the ash pan and keep everybody away from the engine.

Purdie said they inspected the engine after it cooled down and the only damage was three collapsed flues. No broken staybolts, no nothin . . .

EdKing 

They must have had the pops screwed down, too! Wow!

Lucky that one didn't blow.

Seems like an informal standard might have been that at the working pressure the gauge needle would have been pointing straight up.  In other words, on a 400 pound gauge, the needle pointing straight up would have been pointing at 200.  Similarly, a 600 pound gauge for an engine steaming at 300.  That way a guy could see at a glance at where the needle was pointing without having to go read the numbers.

I don't know that for sure, but it seems like a logical thing.

EdKing

boilers are also generally tested to 150% of their working pressure.

That would be a hydrostatic test at 125% of RATED working pressure for railroad locomotive boilers, in the U.S.A.. NOT 150%.

i guess the rules must be different for scale boilers (1:8, 1:12, etc).

most clubs i know require 150% over operating pressure hydrostatic test.

admittedly, these locomotives operate at a much lower pressure than full scale.

So Dave excuse my ignorance, it looks like the gauge was not from a URR 0-10-2 or the 1895 2-10-0 but probably an 2-8-0 or 0-6-0.  Do you know which?  Great find! 

U.R.R. is probably "Union RR", right?

Yep  URR is the Union Rail Road the pride from Munhall to Clairton to Wall

Not sure what it is out of.  I will try to find out.

Dave

Here is the 500lb pressure gauge Hotwater is referring to that is installed on the fireman side on the SP4449.  

Thanks. Nice view of my office, too!

I have been lucky enough to watch you work in your office!

Nick

Fun isn't it, Nick?

Great find, Dave! Very nice to see old pressure gauges that have survived. FWIW, here's a picture of the boiler pressure gauge out of N&W 2164. It has a N&W calibration sticker and the cab#2164 written in chalk on the back.

My Grandfather received this as a gift when he retired from the N&W in 1959. It is currently on the wall to my train room.

Here is another view of Hot's office and 500 lb. gauge. I have no idea whose overexposed finger that is.  :-)

A closer look of 4449's Fireman's gauges. You will note that 4449 is alive and under pressure.

Edward King is right. Any pressure gauge reads the most accurate in the middle 1/3 of the gauge pressure range. So a 500 PSI gauge would be the most accurate from approx. 180 to 320 PSI (PSI = Pounds per square inch) After 30 years in the "Oil Field" a 500 PSI pressure is low pressure to me. I've seen 13,000 PSI on gas wells and I tested wellhead equipment to 15,000 PSI.  I've got a old gauge that is painted red I will have to remove some of the paint to see if it is brass, but I think it came off of a old pump.  Great looking pictures of pressure gauges.

What makes David's gauge a little "extra special" in the collecting world is that it's not only marked for a railroad, it's marked "Locomotive" as well.

I have a nice Ashcroft locomotive guage, brass with a stainless steel face. I was lucky enough to use it for a season on the New Hope Valley Railway before we bought new Ashcroft gauges.