It is probably a neutral zone in the overhead wires. There are different power injection points on the rail network and they have to be isolated from each other.
When a train goes over this dead section the systems move to battery power. There is no traction however so the train has to roll over it.
When battery power is in operation a contactor or high power relay will switch the internal train systems like lighting to battery. The contactor is an electro mechanical power switch and it can make quite a thud.
On the Class 380 train the contactor is incredibly loud and that is probably what you hear. The 380 runs out your way to Newton and Neilston I believe. |