The primary purpose of the Test Track is to provide a facility for testing the Advanced Passenger Train (Experimental) at speeds up to 155 m.p.h.

Features include a reasonable length of straight track, sharp curves, and tunnels, and the line has been laid with different types of track and switch and crossing work for test purposes. The intention is to provide as near as possible a length of track which will be maintained to "typical" standards rather than "better-than-average", so that the results of test work will be representative of the behaviour that can be expected from the Advanced Passenger Train on other main lines on the B.R. system.
 
The Test Track is formed from part of the Down line of the former Midland Railway route from Melton Junction to Nottingham. From Melton Junction northwards, the former Up line is used for traffic to and from Holwell Sidings, and at a point 1471 yards from Melton Junction, a cross-over gives access to the Test line. The northern end of the Test line is at mile post 120, which is 3 miles 406 yards from London Road Junction, Nottingham. The line between Melton Junction and Nottingham was last used for Class A traffic in May 1967 and was closed to through freight traffic in the following October. Trip working over the traffic (former Up) line between Holwell Sidings and Old Dalby ceased in September 1969.
 
The necessary alterations to the Down line to convert it into a test track were carried out by the Divisional Civil Engineer at Nottingham on behalf of the Chief Civil Engineer, London Midland Region, to a specification prepared by the Advanced Projects Division of the Research Department. Civil Engineering work began in April 1969 and was completed by 30 Sept 70, on which date the General Manager, L.M.R. handed over the Test Track to the Research Department, Concurrently with the Civil Engineering work, the Divisional Signal & Telecommunications Engineer was also involved in the project. During the later stages of the D.C.E.'s work on the project, it was possible to use portions of the line for test purposes.
 
An informal visit was arranged for the Chief Inspecting Officer of Railways, Ministry of Transport on 8 July 1970 when he and his colleagues were able to inspect the line and comment on the proposed methods of working. These had been the subject of discussions between the General Manager, L.M.R. and the Research Department the method being that basically applicable to a one-engine-in-steam line.

The control centre for the Test Track has been established at Old Dalby where there is a stabling point for test trains and a small Workshop in addition to the Control Building. These buildings have been erected to designs prepared by the B.R.B. Chief Architect .