73
Bruce in the Peg
If you have an NMRA metal gage, it has several different tabs and slots around the perimeter that can be used to check track and wheels to make sure they are in guage.
Read the instructions that comes with the NMRA gage to see how to use it. You can read a set of instructions online here.
Track gauge is the most obvious -- it's the separation beteen the rails. Put the rails too close together and things will jump the track because the flanges can't fit between the rails. Put the rails too far apart and wheels will drop onto the ties, again derailing.
Check gauge applies to both turnouts and wheels, and it's a critical dimension. It's essentially the distance from the face of one flange to the backside of the opposite wheel when talking of wheelsets, as shown here from the NMRA standards diagram (dimension K):
(Click to enlarge)
For HO, K is 0.603", with a tolerance from 0.596" - 0.605". In other words, wheels can be a bit tight on gauge and be okay, but if they're too far apart, they will cause problems in a hurry.
Check gauge is so valuable because it checks both the wheel spacing and the critical flange dimension (wheels can have a variation in thickness -- check gauge makes sure the flange is where it belongs, no matter how thick the wheels).
The corresponding critical track check gauge is similar ... it checks that guarded track (track with guard rails) is set properly for the guard rails to do their job (guide the wheels to where they need to go). Here's the NMRA track check gauge diagram (dimension C):
For HO, check gauge is 0.607", with a tolerance from 0.605 - 0.614. In this case, track check gauge can be a bit wide and still do it's job (keep the wheels going where they should), but if check gauge is narrow, it will cause problems in a hurry.
In testing out most commercial turnouts, track check gauge through the frog area of a turnout is often too narrow -- exactly the wrong direction of what it should be. This will allow the wheels to pick the frog point and derail. In short, it's one of the main reasons commercial turnouts are not as reliable. The designers of the turnouts thought some "slop" in the turnout check gauge would make the turnout more forgiving -- when in fact the slop makes it more likely the wheels won't go where you want them to go -- and shazam! Derailment!
The flangeways end of the NMRA gage (shown below) allow you to test for this dimension to be set properly.
Most hobby shops sell the HO NMRA gage for a few dollars. If you get yourself a gage and use it, the reliability of your train operation will improve noticeably. The NMRA web site has lots of info on standards and such, and is worth a visit.
Joe Fugate Modeling the 1980s SP Siskiyou Line in southern Oregon
Hey Joe,
I've tried to sign up for your forum but something is seriously messed up. I put in my name as the user name and login name and it says that it already exists. I tried making up a different login name, one I seriously doubt is in use, and it says that login name already exists. Maybe its because I tried signing up once with my email address (jimfitch@juno.com) and its tied to your data base. Can you fix that cause I'd like to participate being an SP fan.
Rio Grande. The Action Road - Focus 1977-1983
Jim, email me offline: joe@fugate.com ... I have a pretty good idea what's wrong.
Blind Bruce wrote:C'mon guys. This may be why my Pacific derails on the Walthers turnouts.
B. BRUCE:
I SUSPECT your problems are elsewhere.
Derailments are Wheels not following the track configuration.
It could be: (1) too tight bolster screws (2) too tight of curves (3) vertical kinks (4) horizontal kinks (5) 'S' curves (6) multiple radii occurance in loose Superflexible type (Atlas) track (7) too lightweight (8) coupler length & geometry (9) Inability to see - since all require different 'fixes' and (10) Yes, the turnout - (in that order) - assuming your wheel flanges aren't 'picking' the points and derailments aren't occuring elsewhere and coming off the track at the turnout.
I've had ALL and EACH of the above, the most recent being (6) a 90o 26" curve of Atlas Code 100 derailing my MDC Atlantic that made 18"r. sectional track curves with ease. REplacing the 'Superflex' with stiffer bending Shinohara cured the problem. It was The ONLY Atlas track left on the whole layout (Gone but not forgotten.
I now have a mix of Shinohara, Walthers,True Scale, track & turnouts left over from previous layouts ($$$ invested), and now Micro-Engineering 70 for new yards. 100 for Mainline, 83 for Passing sidings, and 70 for Yards.
DG, the (ex) 'Derailment King'.]
PS i didn't include 'wheel gauge' because of the difficulty in re-gaging STEAM drivers - besides that their main problem has mostly been too-tight of curves to navigate.