The seven contractors are: Amey Colas, Babcock Rail, Balfour Beatty, Carillion, Grant Rail, Jarvis, and Trackwork.
Network Rail added that over the next five years high levels of investment in track renewals will continue with almost £4bn being invested.
Total outputs for the five years will remain as previously planned although adjustment in phasing in the early part of the period will result in less volume of track renewals in the first year to allow time for new, more efficient ways of working to take effect delivering the value for money needed to meet tough ORR output targets as well as being less disruptive to passengers and freight users.
Simon Kirby, director infrastructure investment said; "We are committed to continue to invest in our railway to deliver ever higher levels of reliability for the passenger and freight users. But we must deliver value for money for this work and it makes sense to take advantage of new, more efficient methods of working in our future planned work.
"With smarter and more mechanised ways of carrying out track renewals coming on stream in a few years time, reducing volumes next year and ramping up in the years that follow will help to deliver the savings we need if we're to meet ORR output targets."