, around of the route uses automatic block signalling for train operations – concentrated in high density routes, large cities and junctions. Remaining routes are based on absolute block signalling with trains manually controlled by signalmen from the signal boxes typically located at stations. Few low density routes still use manual block signalling methods with communication on track clearance based on physical exchange of tokens. In a few sections, intermediate block signalling is provided to further enhance line capacity with minimal investment. , 602 block sections have intermediate block signals on IR.