Normally, the size of virtual transition is taken as 14.6 meter on B G, 13.7 meter on M G and 10.three meter on N G The cant or superelevation is gained over the virtual transition. For excessive speeds, in group ‘A’ and ‘B’ routes, a straight with a minimum size chinese youxuan kkr 6b of fifty M, shall be stored between two transitions of reverse curves. High pace routes the space to be kept will be 30 metres. G., straights lower than 50 metres between reverse curves and on M.
The unique round curve TC is tangential to the straight at T. The curve is shifted to ZY and TZ is the amount of shift. The transition curve MNP bisects the shift TZ at N. A typical example of figuring out most permissible speed on a curve, calculating the length of transition and detailed calculation of laying the transition are given in sub-para.
In such circumstances, the cant ought to be so chosen as to allow the very best speed on the curve as an entire. The first summation at any station, gives the cumulative versine difference at each station. To start with this worth for station ‘ 0 ‘ is identical as the versine difference (Col. 4). Since the sum total of the prevailing and the proposed versines is the same, the determine against the last station might be ‘zero’ (Col. 5).
The identical pace and the identical cant shall be allowed on the outer highway. In the case of 1 in 8-1/2, 1 in 12 and flatter turnouts provided with curved switches, higher speeds as permitted underneath approved special directions may be allowed on the turnout aspect, provided the turn-in curve is of a normal appropriate for such higher speeds. Extra shoulder width of ballast of 150 mm should be supplied on the surface of such turn-in curves. When these conditions are glad, the speeds indicated below may be permitted on turnouts supplied with curved switches. While allowing speed beyond 15 kmph, provisions of para 410 can also be saved in view.
The stations should be at 10 metres intervals and versines should be recorded at these stations with overlapping chord of 20 metres. Curves with cross avers – On curves on double line connected by cross over street, the velocity and the cant for both roads are ruled by the inside highway to which the cross over road is a curve of contrary flexure. On the outer road, it is a curve of comparable flexure. The permissible pace and the mandatory cant on the inner street shall be calculated in accordance with Para 413.
Indication of cant on track- Superelevation or cant should be indicated by painting its value on the inside face of the net of the inner rail of the curve and at every versine station, begining with zero at the graduation of the transition curve. The worth of cant ought to be indicated on the round curve at its begining and at the end. In the case of long round curve the cant worth should be indicated at intermediate stations at a distant not exceeding 250 metres. The imply shear wave velocity to a depth of 30m , established within the western United States, is the present web site classification criterion for figuring out the seismic design floor movement, taking site amplification potential account into.