The rail infrastructure body said the firms will deliver £2bn of works in its national electrification programme over the period.
Several major electrification contracts are already in progress covering the period but Network Rail wants to increase the number of suppliers it uses because of the scale of the programme.
Firms or consortia will be expected to carry out detailed design, supply, manufacture, construction and commissioning services for all aspects of electrification and associated infrastructure.
This includes overhead line work, power supply, distribution, civil engineering work, on track plant, signalling works, telecoms and track works.
Contract Jo Dunn at Network Rail’s Milton Keynes office for further details. Tel 01908784080 or emaill: ipcontracts&commercial@networkrail.co.uk