wkaiser@[EMAIL PROTECTED]
wrote:
[...]
>
> V grooves in the ties may be a good idea. The ties WILL move around in
> the ballast, and could change the track gauge.
I don't think so. Those grooves will accelerate the tendency for rail
bases to cut into the ties and ultimately break them. Spikes (or bolts)
hold the ties in gauge. Tie-plates are available to spread the load from
rail to tie, and prevent the rail base from cutting into the tie.
If the ballast is properly built and maintained, the ties will move very
little if at all. The purpose of ballast is a) to hold the track in
place; b) spread the weight from track to roadbed; and c) to provide
drainage. Ballast should be clean, screened crushed gravel of a suitable
size - in the case of OP's working railway, about 1/2" to 1"; crushed
gravel rather than pit-run so that it packs when tamped. Ballast width
at the top should be about 1.3 to 1.5 times tie length, and at the base
about twice tie length. Its depth below the ties should be at least
equal to tie thickness - twice tie thickness or so is better, but
requires a lot more material. The roadbed should be graded with a slight
crown so that water drains away on both sides. Super-elevation on
curves, if any, is created by placing more ballast underneath the high
side of the track.
The above is adapted from railway engineering texts included on the
reading lists of the "Materials and Processes" and surveying courses
that I took in 1st year engineering many years ago.
HTH
--
wolf k.
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