Hello everyone, I remember the first time when I discovered what the Pennsylvania Railroad 6-4-4-6 S1 class duplex steam locomotive was. It was quite the large ridged framed duplex locomotive as I found out. I discovered it via a tribute video. I have watched it again since then, and learned that many railroads has their own sort of endurance and testing facilities, in which the locomotive would run at various speeds on a large rolling road, as I saw the S1 being tested running on it while steamed up.I have to ask if these facilties still exist at some modern locomotive building and rebuilting plants. This also gave me an idea. It would be neat to have your own speed testing facility as a showpiece and a fun way to test your locomotive speeds, as if it where a real testing facility. I am not sure of how you would move the locomotive onto the rolling road/testing wheels via basic DCC/DC control from the track percisly, or make it look realistic as its easier to place your locomotive via hand and place each of the powered drive wheels each rolling rods wheel sets. I will have to draw up and think of some concept art of how this could work, and make another thread post on it. If anyone could tell me the right term or if speed testing is correct I would appriciate it.
Are you talking about this:
http://testplant.blogspot.com/2011/08/altoona-prr-test-plant.html
Looks interesting.
Mike.
My You Tube
He means locomotive test plants, of the sort pioneered in North America by Purdue (under Goss) in the 1890s
https://www.purdue.edu/newsroom/purduetoday/didyouknow/2015/Q1/did-you-know-purdue-locomotive-testing-plant.html
The PRR test plant was installed and shown off at the exposition in 1904, and moved to Altoona afterward. The very detailed and fascinating early test reports are available from Google Books and contain some fascinating information (one of the locomotives carefully described and tested was an ATSF tandem-compound 2-10-2)
There were a number of different types of test plant, and some famous counterparts in France (e.g. Vitry) and Britain (e.g. Rugby). I believe Riddles has a discussion of testing on a 'roller rig' that can be accessed and read on line, but until I recover from hard-disk crash I can't provide the link directly.
In some cases the rollers were not just dynamometer 'braked' but could be motored at speed to test other characteristics, such as drifting.
These are not, and shouldn't be thought of as, perfect replacements for good road testing with a (brakable) dynamometer car. I won't go into the reasons in detail but both have their clear place if you can afford them. An early introduction to the subject is here:
https://babel.hathitrust.org/cgi/pt?id=uiug.30112070529588&view=1up&seq=6
You don't need a huge building with massive rolls, either: the one for T1 5550 will double as a transporter frame...
In practice the easiest way to get the locomotive in place is to use bridge rails in sections, then Jack and stabilize the locomotive, then align the roll spacing under the drivers. You will have instrumentation at the drawbar as well as at the rollers, and a considerable amount of blocking and bracing in case of 'surprise' (look at some of the PRR Q2 test records for examples!)
In a model the easiest way is to copy the arrangement Fine Art Models used: there are semicircular cuts 'from below' in the rail where the wheels will rest, with just enough gap at the railhead to accommodate the contact patch. If you want larger rollers you can use the visually-small ones as idlers. With the rollers locked you should be able to run the locomotive onto the "plant" with perhaps a little GHA to get things aligned.
To my knowledge none of these plants was extensively used in the 'diesel era' and they have all been removed. However, the use of a roll dyno of appropriate hp capability would certainly be possible were any contemporary designer to want.
Looking up a different issue, I came across the testing of P2 'Cock O' the North' in 1934 that might be inspiration for how a model test plant might look:
https://m.youtube.com/watch?v=eUo5bRxl0r0
OvermodTo my knowledge none of these plants was extensively used in the 'diesel era' and they have all been removed.
I remember seeing freshly rebuilt diesel locomotives roll out of the Collinwood backshop on the NYC east of Cleveland, Ohio, and sent to the "test shed".
They had a setup where the test locomotive could be wired to resistor banks and a load test could be performed. Cabling would be run directly to the 600 V. cabinet. On "covered wagons" the lines would be run out the side door if present or out the window or porthole.
I don't know how long of a duration the load tests would be conducted but there were times I spent maybe three or four hours there and the diesel was still running at "run-8" for the whole time. I'm sure there were meters wired so the output of the main generator(s) could be monitored.
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.475.5884&rep=rep1&type=pdf
Good Luck, Ed
gmpullmanThey had a setup where the test locomotive could be wired to resistor banks and a load test could be performed. Cabling would be run directly to the 600 V. cabinet. On "covered wagons" the lines would be run out the side door if present or out the window or porthole.
That's not what a test plant does -- it would involve putting the locomotive on rollers to assess actual wheelrim performance while monitoring the electricals.
Someone with current access to JILE can look at the history of the Rugby facility, which was in fact used to test a range of early diesels, to get a better idea of the specific reasons dynamometric testing of modern power had ceased effectively by the 1960s as claimed.