QUOTE (KODIAK BEAR @ 27 May 2007, 12:55) <{POST_SNAPBACK}>what on earth is peco 75 and peco 100 ?????
The number (or code) indicates the height of the rail in thousandsth of an inch. Thus the smaller the number, the smaller the rail. What it doesn't tell you is the cross-sectional shape, or in the case of flat bottomed rail, the width of the foot. This means that although rails of the same height might be available from several manufacturers, you can't necessarily assume they will be the same in all other dimensions, and may not fit any premoulded sleeper assemblies.
I found exactly this problem when trying to use some flat bottom rail from C & L that I already had with the concrete sleeper bases produced by InterCity Models. The foot of the rail was really too wide for the Pandrol rail fastenings, and caused the sleeper material to deform during assembly. Using the recommended code 82 rail solved the problem, but you could hardly tell the difference just by looking at the rails beforehand.
The number (or code) indicates the height of the rail in thousandsth of an inch. Thus the smaller the number, the smaller the rail. What it doesn't tell you is the cross-sectional shape, or in the case of flat bottomed rail, the width of the foot. This means that although rails of the same height might be available from several manufacturers, you can't necessarily assume they will be the same in all other dimensions, and may not fit any premoulded sleeper assemblies.
I found exactly this problem when trying to use some flat bottom rail from C & L that I already had with the concrete sleeper bases produced by InterCity Models. The foot of the rail was really too wide for the Pandrol rail fastenings, and caused the sleeper material to deform during assembly. Using the recommended code 82 rail solved the problem, but you could hardly tell the difference just by looking at the rails beforehand.