Pilot doghouses?

These doghouses were only used when testing and documenting locomotive performance. One or two men rode up there, inserting indicator cards into a device attached to the valve gear that diagrammed the action of the valves, steam chest pressures, back pressure, speed, etc.

Test were run at various speeds, throttle positions and cutoff settings so the locomotive manufacturer or railroad involved had a documented record of the locomotive's performance.

When the tests were completed, the doghouse was removed.

There are pictures in Alvin Stauffer's "Thoroughbreds" of the original New York Central J-1 Hudson #5200 with a similar structure on the pilot during testing. It looks like a custom built affair. The accompanying text says that the structure protected test personnel and their instruments, which were used to measure cylinder and valve operating conditions.

Like this???

Thanks everyone, including Snoopy.  Brasher's book talks a lot about building a dynanometer car and using it, etc., but mentions nothing about the pilot doghouses beyond having those pictures.  The book does give all the data from those Sept. 23, 1938 tests though, and it is interesting.  

Much appreciated.

This may be of interest to you.

Testing a Steam Locomotive

Oh yes!  Thank you very much, Big Jim, this was both very helpful and quite interesting.

The "Indicator Cards" produced by the instrumentation on the locomotive produced diagrams of pressure as it related to valve position.

Here's an illustration of what the indicator card was measuring. That this is NOT an actual indicator card...it is a well-done diagram of what the indicator card is measuring.

The cutoff represented in this diagram is set at about 30% (fairly short) and the steam works expansively for the remainder of the stroke.

Here's an actual indicator card:

This card has two diagrams on it because it is showing the results from BOTH cylinders on one card.

The Timken locomotive had a dog house added to her right side during testing on the NP.  It was very much needed in a Montana winter.  The need to go to the length of building a dog house for people to occupy and take instrument readings also illustrates the degree of difficulty involved in remote data acquisition given the technology of the time.

Note the dynamometer car behind the tender.

See the Ron Nixon collection for more.

http://www.morphotoarchive.org/rvndb/

It must've been an interesting ride up there...

Rusty

Thanks guys!  This is good informaton and very interesting. 

One or two brave men!

And, according to some discussion I found in Brasher's book and on-line, very uncomfortable, too!  

Oh yeah...riding up there in the middle of January was a LOT of fun!