I bought two gages at an antique shop, both made by the Beacon Gage Co. Marked PC 88882. Their range is 0 to 160 psi, they are also marked Westinghouse test gage, and one is marked Westinghouse Air Brake. They are all brass and about four inches in diameter.
Were these to test the other gages on locomotives? They have 3-87 and initials penciled on the face like they were checked for accuracy on that date. How accurate would they have been when new and what is their allowable inaccuracy. I just want to use them to test non railroad, non commercial gages.
Thanks,
Mike

Mike,
An indicating gage/gauge or meter can be labeled to mean anything.

Remember Johnny Carson's audience applause meter?

Or for the 21st century crowd, remember when Apple admitted that they were stunned to find that the
formula they used to calculate how many bars of signal strength displayed on the iPhone was totally wrong?

The brass gauges you found are likely beautiful and in still working condition.

As for their accuracy?

That opens up a whole new topic outside the scale/scope of this forum,
and likely not practical or possible to measure.

John

Search for "dead weight testers" for examples of a way to test gauges very accurately. From personal experience, one way to impress an FRA locomotive inspector is to show him a working example on a shelf in the shop.

Hi,

As an anicdotal comment on the accuracy of your gage, I learned civil engineering and surveying in the 1970s before handheld electronics were available. It was all optical and tape measure (or chain).

For Government use, the chains had to be certified every so often (I think once a year) to the US Bureau of standards reference block. This was before measuring wavelenghts of light was affordable.

A certificate saying your nominal 100 foot chain was 100.2 feet long (or some such) allowed adjustment to the accepted standard. There was a whole set of steps that allowed you to calculate how the temperature affected your chain. How the slope of the ground had to be adjusted. How the sag in the chain (if not laid on the ground) shortened the chain. How the humidity might affect the chain and so forth. Lots of error possibilities.

Now-a-days with GPS, some errors still occur but with a lot less worry.

How accurate is your gage? I would try to look up the manufacturer's documentation for information.

As for calibration, if would need to be verified back to some standard (government or something else).

I hope this might help a bit.

DOug vV

As a rail interest, the mathematical shape of an unsuported rope or wire suspended at both ends is called a catenary - think PRR, NYNH&H, CCS&SB, CMSP&P or any other high speed railroad with overhead wires.

I believe that PC 88882 is still a good WABCO number. That number should be a 160 psi gauge. Beacon could have well made it for Westinghouse Air Brake. Your reference to penciled numbers are probably calibration dates. Depending on the use, there will be an FRA calibration interval. Normally you note when it was calibrated and when it needs to be calibrated next.

G.F.Payne
Baltimore, MD

These gauges were supplied on the Westinghouse Test Racks used to test air brake valves. Our AB Test Rack has a series of these gauges mounted across the top.

Thanks for all the replies.
Mike

Four 8s and a deuce. These could show up anywhere a high-accuracy
gauge is needed for testing, such as on a fixed test rack, single-car test
device, gauge comparator.

According to WABCO test code TC-178, this single-pointer, 3.5", 160#
test gauge must be accurate to within 1.5# between 0 and 10# (tapping
the gauge is permitted to overcome needle friction) and also between
110# and 160#. Within the 'sweet spot" of 10 to 110#, the gauge must
read within 0.5# of the calibrated standard and no tapping is permitted,
i.e. the gauge must move smoothly without jerking or jumping more than
0.5# These gauges were generally calibrated against a dead-weight tester
in 10# increments.

As a practical matter, since the scale on this gauge is marked in 1# divisions,
it is difficult to discern the reading with a precision better than 1/2# anyway.

These accuracy standards predate the modern ASME B,A, 2A, 3A, 4A system
which requires the stated accuracy throughout the entire range. Since 0.5# is
about 0.3% of full scale for a 160# gauge, these test gages are between 2A
and 3A grade on a modern test gauge. These 88882 test gauges were not generally
temperature compensated and could be adjusted for span and zero but not
linearity.

When running through a test code, the 0.5# accuracy is plenty good enough.