Technical Guide on Derailments PDF

CAMTECH/M/3 113 APPENDIX „B‟ Standard Dimensions of Permanent Way SR No. Description BG MG 1. Gauge 1676 1000 2. S...

CAMTECH/M/3 113 APPENDIX „B‟ Standard Dimensions of Permanent Way SR No. Description BG MG 1. Gauge 1676 1000 2. Slopes of formation 1. for embankment 2:1 2:1 2. for cutting 1:1 1;1 3. Centre to centre distance of track 1. minimum 4265 3660 2. recommended 4725 3960 4. Length of rail 13000 12000 5. Clearance of check rails at level crossing 1. minimum 51 51 2. maximum 57 57 6. Clearance of Check Rail 44 41 on the curves 7. Distance between the centre of track and the face of platform 1. Max. 1680 1345 2. Min. 1670 1335 A TECHNICAL GUIDE ON DERAILMENTS April ‘98 CAMTECH/M/3 114 SR No. Description BG MG 8. Height of passenger platform above rail level 1. Max. 840 405 2. Min. 760 305 9. Standard length of tongue Rail 1 in 8½ straight 4725 4116 1 in 12 6400 5485 1 in 12 Curve 7730 6700 1 in 16 curve 9750 7420 10. Check Rail clearance at turnout 1. Min 44 41 2. Max 48 44 11. Throw off switch 1. Max 115 100 2. Min 95 89 12. Min Thickness of Blunt nose 6 6 13. Size of ballast of track 50 50 14. Top width of Ballast 3353 2286 A TECHNICAL GUIDE ON DERAILMENTS April ‘98 CAMTECH/M/3 115 A TECHNICAL GUIDE ON DERAILMENTS April ‘98 CAMTECH/M/3 116 APPENDIX „C‟ Calculation of Gauge slackness which may cause derailments Gauge = 1676 mm Wheel Gauge = 1600 mm Difference = 1676-1600 = 76 mm Thickness of flange = 28.5 mm Thickness of both flange = 28.5 * 2 = 57 mm Play between rail and flange = 76-57 = 19 mm Condemning flange limit = 16 mm Wear permissible for both flanges = (28.5-16)*2= 25 mm Slack permitted up to 4 degree curve = 13 mm Total permissible play between flanges & running edges of rail = 19+25+13 = 57 mm Width of tyre = 127 mm Slackness required to derail a stock =127-57= 70 mm The above calculations are normally advanced to prove that the slackness in gauge to the tune of 70 mm can not be a cause of derailment. However this logic applies only in case of wheel dropping purely on account of slack gauge. In actual practice, even lesser than 70 mm gauge slackness may cause increased lateral oscillations and build-up of excessive flange forces thereby resulting in derailment of stock. A TECHNICAL GUIDE ON DERAILMENTS April ‘98