Abstract :
The paper treats of the various factors which enter into consideration in the design of a 600-volt contact rail system. The weight of rail to be used depends upon conditions met with in each case, but in general, a heavy rail is preferable from all points of view. The question of quality is rather indeterminate, but in general, it is not advisable to use soft steel until the weight has been brought up to at least 80 lb. (36.28 kg.) per yard; however, consideration should be given to it above this weight. Insulating and supporting is a mechanical problem which must be decided upon local conditions. The method of bonding and jointing to be used depends upon size and section of rail used. With standard rail sections the foot bond is the most satisfactory, and with special sections of rail a copper welded joint will be very satisfactory. Provision must be made to control the expansion and contraction of rail by cutting it into sections and anchoring each of these sections. Various methods of connecting rails are described, together with special devices which will be required. The costs of constructing a single-track mile of contact rail using 50-lb. (22.68 kg.) rail is $3,284.29, while the cost of the same amount of 80-lb. (36.28 kg.) rail is $4,028.55. The average maintenance cost per mile of rail, exclusive of entire renewal, is $80.00 per mile per year.
