scope:

This procedure details the Telecoms Clearance process that shall be applied for new or upgraded fixed transmitters on Network Rail land or property, whether or not they are mounted on towers, buildings or other structures.

Where possible the procedure will also be used to mitigate the risk of new and upgraded fixed radio transmitters off Network Rail property, but within 100 m of Network Rail track.

This procedure describes the process for telecoms clearance on a site-by-site basis. It does not address approval of the fixed transmitter design.

The procedure also provides a process for controlling the risk posed by low power transmitters, such as wireless LANs.

This procedure is written to ensure that the maximum field strength which enables interference-free operation of trackside systems is not exceeded anywhere on the network, so no restrictions are made on the positioning of Signalling or Telecommunications equipment in any future renewals schemes.

This standard does not cover any maintenance requirements related to the radio equipment or tower structures.

This standard does not cover mobile transmitters which are subject to their own approvals through the product acceptance route, nor to train-borne transmitters, which will be subject to its own safety review.

Purpose

Radio transmitters can potentially interfere with Network Rail operational systems, including Signalling & Telecommunications (S&T) systems. The purpose of this procedure is to detail the telecoms clearance process to reduce the risk of interference from fixed transmitters to as low as reasonably practicable (ALARP).

The principal fixed transmitters that may cause interference with Network Rail systems are:

• Network Rail's GSM-R network, which will include over 2000 new trackside radio towers
• Radio transmitters on co-existent or adjoining rail networks
• Third Party radio transmitters on Network Rail property and Network Rail property leased to TOCs and FOCs
• Third Party radio transmitters off Network Rail property, but within 100 m of Network Rail track

The operational systems most likely to suffer interference from fixed transmitters are:

• Network Rail's existing and proposed radio systems, including GSM-R, IVRS, CSR, NRN and RETB
• Trackside systems, including S&T systems. For the equivalent field strength, low frequency transmitters (particularly those lower than 200 MHz) are more likely to cause interference to trackside systems than high frequency transmitters
• Train-borne radio systems