Fast Tracks

Is it possible two use two different (But close mind you!) codes of rail in the same jig? In my case, codes 55 & 40 ME rail in an HOn3 jig? Since I am planning to use code 55 rail for the main line on my HOn3 layout, and code 40 for sidings, branches, and industrial areas. And it would be a bit of an inconveinience to have two buy two of the same jigs, just because I'm using two different codes of rail.

ME code 55 rail base is 0.054" wide.
ME code 40 rail base is 0.039" wide.

These are way different in size for the fixtures to self gage and be reliable.

Using codes 70, 75, 81, and 83 in a fixture for code 70 works just fine as these have very close tolerances with each other as to rail bases and rail heads.

For HOn3 and the smaller rails, using a code 55 fixture will be self gaging with code 55 rail and an excellent choice. For the few code 40 situations, you have to rely on using track gages with the code 40 while placed into the fixture. Also use of some feeler gages or correct bits of shim stock when assembling the frogs and setting the guard rails would be important. When setting the guard rails - be certain you are setting them for correct check gage and not flangeway spacing. Checking and verifying with the NMRA gage is very critical when using the smaller rail in the larger code fixture.

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-ed mccamey-
COSLAR RR - http://www.coslar.us/
NMRA Standards and Conformance Department
PROTO & FINE Scale Coordinator
I estimate I have about 5 pounds of coupler springs somewhere in the vicinity of my workbench.

so i will not have to buy a c83 and c70 fixtures for a turnout

PROVIDED you are using Micro Engineering code 83 and code 70 rails, the ME code 70 fixtures will work with both. Using an ME code 70 fixture with other brands of code 83 rails are chancy or a non-starter. There's a lot of differences in the rail profiles beyond the height between the various manufacturers.

An ME code 70 fixture will work with ME code 83, LaVancil code 81, C&L code 75 (perhaps Peco code 75 as well), and ME code 70. Using even smaller rails along with careful gaging is doable - but not without extra cautions for alignments.

_________________
-ed mccamey-
COSLAR RR - http://www.coslar.us/
NMRA Standards and Conformance Department
PROTO & FINE Scale Coordinator
I estimate I have about 5 pounds of coupler springs somewhere in the vicinity of my workbench.

thank you
im going to use the ME track and only ME track so i should be ok im going to buy the code 83 fixtures for all my turnouts since there is no price difference

The code 83 rail base is actually 0.003" smaller than the code 70 rail base. If the fixture does not enough allowance, you may find that the code 70 rails will be too tight in a code 83 fixture. Code 83 and code 70 will work with a code 70 fixture and maintain alignments within allowances.

Here's a chart of the rail sizes:

_________________
-ed mccamey-
COSLAR RR - http://www.coslar.us/
NMRA Standards and Conformance Department
PROTO & FINE Scale Coordinator
I estimate I have about 5 pounds of coupler springs somewhere in the vicinity of my workbench.

ok looks like ill buy c70 thanks for all your help

As one additional note. Older batches of ME code 83 rail were actually much larger than the present (last 5 years of production). Using present ME code 83 and code 70 rails, the chart is correct. If you secure an older batch of ME code 83 rails - then the bets are all off.

You may also note that using code 70 rail joiners will be better for code 83 rails usage. Likewise, using code 83 rail joiners for code 70 rail is better. The ME rail joiners are very tight and many find them difficult to use. Using opposing joiners gives the little additional clearances that are easier to work with. Having a rail joiner 'spreader' made from a piece of filed taper rail and mounted in a handle to use on the joiners before inserting on the rails is a very helpful technique.

Ah - the march of 'progress'!

_________________
-ed mccamey-
COSLAR RR - http://www.coslar.us/
NMRA Standards and Conformance Department
PROTO & FINE Scale Coordinator
I estimate I have about 5 pounds of coupler springs somewhere in the vicinity of my workbench.