Re: Cleaning Ballast - Why do they need to do this?

[craigd@lios.apana.org.au (C. Dewick)]

In <7ptfmi$32l$1@mulga.cs.mu.OZ.AU> cmgord@ecr.mu.oz.au (Christopher_Martin GORDON) writes:

>The requirement for Ballast is to keep the track bed dry and the sleepers dry.
>For concrete sleepers this donsn't realy matter, but you still need to keep the 
>track bed dry and free of water.  Ballast is a good way of doind this, but if
>the ballast is dirty then the water will not drain away.

>Same thing applies to roads you need to keep the sub base dry or the road will
>crack and stuff up.  

>Having a wet track base will result in movement of the track base and you will
>get "speed hump" tracks and do more damage to the trains and tracks.

Track laid with concrete instead of timber tends to 'pump' more on soft
sub-roadbed because the concrete is *much* heavier than timber, and so any
seepage of fluid from below the track is accelerated more than where timber
has been used.

Regards,

Craig.
-- 
            Craig Ian Dewick            |       Stand clear - jaws closing
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