explosive depth hardened

7/22/2019 Explosive Depth Hardened

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Explosive Depth Hardened (EDH) CMS Crossing

The initial hardness of CMS Crossing is about 180-220 BHN while that of cast steelwheels is 320-340 BHN. By the time hardness of CMS Crossing is increased throughwork hardening, wear to the extent of 2 to 3 mm takes place quickly.

Explosive hardening process leads to increase in initial hardness to about 350 BHN inwear prone areas which reduces wear at nose and wing rails considerably leading toincrease in service life of CMS Crossing.

EDH CMS crossing is recommended for high GMT & heavy axle load route to reducethe requirement for reconditioning and increase in service life.

In addition, geometry is not retained well in ordinary CMS Crossing. Wear in EDHCrossings is more regular which shall lead to less impact leading to reduction inmaintenance effort.

EDH CMS Crossings manufactured by M/s VAEVKN have been supplied for field trial atNR and SCR. The performance of 52 Kg 1 in 12 EDH CMS crossings laid in NR and 60Kg 1 in 12 EDH CMS crossings laid in SCR have been found to be satisfactory. Wear atNose and Wing rail in EDH CMS Crossing have been found to be less by 1 mm to 3.5mm compared to Ordinary CMS Crossing.

In view of satisfactory performance in limited field trial, Railway Board has approvedextended field trial in Sept., 2012 - 50 sets each of 60 Kg 1:12 in NR, NCR, ER & SCRand 50 sets each of 52 Kg 1:12 in NR, NER &NFR.

EDH CMS Crossing is widely used in foreign railway systems. The same has also beenused in DMRC. According to Technical Standards of Track Structure for MetroRailways approved by Railway Board, the CMS crossing to be used on mainline shallbe subjected to explosive hardening and All CMS crossings shall have a minimum initialhardness of 340 BHN.