Signals at most stations are interlocked using panel interlocking, route-relay interlocking or electronic interlocking methods, which eliminate human error. IR uses track circuiting, and block proving axle counters for train detection. , 5,886 stations across IR have interlocked stations and multi-aspect signalling. Around 99% of key routes (A, B, C and D) have track circuitry or block proving axle counters for automated train detection. IR has about 59,105 route kilometers of optical fiber cable network across India, that is used for train control, voice and data communication. Around of the route is covered by GSM-R based Mobile Train Radio Communication.