1 In 1973, the whole rolling stock of the Piccadilly Line - some 86 trains - was replaced. In 1995, LUL became aware that axle box failures on the line were increasing. It therefore undertook a programme to replace the bearings in the boxes.
2 LUL believed that this work programme would solve the axle box failures until the rolling stock was replaced in 2014. However, in early 2003, operators and engineers variously identified axle box defects on three units of the fleet. Infraco JNP undertook an audit of the axle boxes and bearings on the fleet and established that the boxes were wearing faster than expected because of:
■ A timetable change introduced in 1995/96, which effectively increased the off peak nearer to a peak timetable and thus increased the annual kilometres travelled by each train.
■ A train interior refurbishment that increased each car's weight by one tonne.