Rail services resume between Northampton and Milton Keynes
Work had taken place over the festive period
Trains are running once again on a stretch of railway that was upgraded over Christmas.
Over 14 days from Christmas Eve, four railway lines along a mile-long section of track between Milton Keynes and Northampton were replaced to improve future journeys for passengers and freight on the West Coast Main Line.
Hundreds of workers replaced 130 track panels across the junction- described as Britain's biggest Christmas jigsaw- renewed the foundation stone known as ballast below the track, and overhauled points, switches and crossings.
A number of delays had been reported at the junction over the last few years, and there are hopes the work will reduce disruption along the West Coast Main Line.
All lines were reopened at 04:00 GMT on Monday.