Cast Manganese Steel Crossing (CMS Crossing)
Built up or fabricated crossing has a large number of separate units to which attention must be paid during service. The vee formed by the point and splice rails is weakened by heavy machining of the head and foot.
To afford better resistance to wear and reduce the cost of maintenance and frequent renewals, cast manganese steel solid crossings have been evolved. Other advantages of cast manganese steel solid crossings when compared to common fabricated crossings are as follows:
1. Fabricated crossings demand higher maintenance labour to keep the bolts and fastenings tight.
2. When the looseness develops in them, high rail stresses are set up.
3. They lack vertical stiffness.
4. The change of section points in the assembly of rails are stress raising features, which are compatible with the best engineering practice.
5. CMS crossings are particularly useful in continuous welding of rails through points and crossing as they do not need any special strengthening so necessary for fabricated crossings.
Technologies have been developed for butt welding of CMS crossing with the plain line rails by interposing a compatible transition piece of alloy steel.
This technology patented by M/s. Voest- Alpine of Austria, is being obtained for Indian Railways for use on high speed heavy density routes.
CMS crossings are costlier but they [more than] repay for their initial investment in their longer life.
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