Class F main line concrete sleepers a proposal to reduce the number of prestressing wires from 28 to 26 in the F.7 design, i.e., the design for use with MRC.6 baseplates (E-348)

The designs of concrete sleepers of F strength specifically for use with cast iron baseplates and Kills C clip fastenings have been described fully in Report E.219 dated April 1959. The design recommended in report E.219 (8'-3" long, 6?" deep at the rail seatings and with 28 wires) has...