The New Measurement Train (NMT), is a specialised train which operates in the United Kingdom to assess the condition of track so that engineers can determine where to work. It is a specially converted High Speed Train, consisting of two Class 43 power cars and five Mark 3 carriages. It can check the condition of most main lines and some secondary routes operating a 13-week rolling cycle. The train is permitted to travel across any part of the network where HSTs are permitted, as well as High Speed 1.