IR uses a range of signalling technologies and methods to manage its train operations based on traffic density and safety requirements.

As of March 2019, around 3,039 km (1,888 mi) 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 signal men 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.
As of March 2019, 574 block sections have intermediate block signals on IR.

IR primarily uses coloured signal lights, which replaced semaphores and disc-based signalling (dependent on position or colour).
IR uses two-aspect, three-aspect and four (or multiple) aspect color signalling across its network.

Signals at most stations are interlocked using panel interlocking, route-relay interlocking or electronic interlocking methods that eliminate scope for human signalling errors.
IR uses track circuiting, and block proving axle counters for train detection.
As of March 2017, 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.
Also, IR has about 55,385 route kilometers of optical fiber cable network across India, that is used for train control, voice and data communication.
Around 2,500 km (1,600 mi) of the route is covered by GSM-R based Mobile Train Radio Communication.

In December 2017, IR announced that it will implement ETCS Level 2 system for signalling and control on key routes with an investment of ₹12,000 crore (US$1.7 billion).
Currently IR uses Centralised Traffic Control (CTC) on the busy Ghaziabad – Kanpur route and real-time train monitoring systems on Mumbai and Kolkata suburban routes.
IR uses a range of signalling technologies and methods to manage its train operations based on traffic density and safety requirements.
As of March 2019, around 3,039 km (1,888 mi) 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 signal men 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. As of March 2019, 574 block sections have intermediate block signals on IR.
IR primarily uses coloured signal lights, which replaced semaphores and disc-based signalling (dependent on position or colour). IR uses two-aspect, three-aspect and four (or multiple) aspect color signalling across its network.
Signals at most stations are interlocked using panel interlocking, route-relay interlocking or electronic interlocking methods that eliminate scope for human signalling errors. IR uses track circuiting, and block proving axle counters for train detection. As of March 2017, 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. Also, IR has about 55,385 route kilometers of optical fiber cable network across India, that is used for train control, voice and data communication. Around 2,500 km (1,600 mi) of the route is covered by GSM-R based Mobile Train Radio Communication.
In December 2017, IR announced that it will implement ETCS Level 2 system for signalling and control on key routes with an investment of ₹12,000 crore (US$1.7 billion). Currently IR uses Centralised Traffic Control (CTC) on the busy Ghaziabad – Kanpur route and real-time train monitoring systems on Mumbai and Kolkata suburban routes.
Indian Railways