Scientific paper ID 1204 : 2015/3

This paper refers to trams operating in Sofia. Consider the problem of mismatch between the existing rules on the undercarriage of trains and track built with chute rails.The study is part of the problem of searching for the cause of the prolonged contact of non-operative side of the rims of the wheels with the rim of the rails. This leads to intensive wear of the initial non-operative part of the rims of the wheels, which reduces the lifetime of the wheels.The report compares the geometric standards for wheelsets and track on the basis of regulations and engineering documentation of railcars and standards for the track. The study of the problem has not established connection with the implementation of various norms.In the paper are examined all possible options of combining the dimensions of wheelsets and straight stretch of track built with chute rails. It has been found that in some embodiments there is contact of the non-operative part of the rim with the rim of the rail. In one of these variations such contact occurs significantly before reaching the pledged in the engineering documentation wear limit of the rim of the wheel.Based on calculations made in the report there is a proposal for adjustment of the minimum thickness of the rim and the positive deviation in track built with chute rails. With the proposal the contact of the non-operative part of the rim of the wheels and the rim of the rails for oscillation in plan movement of the bogie is avoided.