southern442
Established Member
If it's in the third rail area your hearing this sound, could it be the sound of the shoe gear hitting the conductor rail ramps, how many pinging sounds do you hear before the train arrives?
Living in a third rail area myself, I also thought it was the third rail making that noise, but diesel and overhead trains also make that noise. The third rail does make a similar noise too, as there is an additional pinging/vibration when a 377 comes along that is absent when a 171 comes.