In the early hours of Monday morning Network Rail engineers completed the latest upgrades to the Great Northern Great Eastern (GNGE) line.
During a 16-day closure of the railway, 1930s mechanical technology was replaced with modern electronic systems now controlled from Network Rail’s Signalling Control Centre in Lincoln.
Workers installed 15 new level crossings and 15 miles of the latest signalling technology to improve reliability.
Phil Verster, route managing director for Network Rail, said: “The GNGE line is an important route for both freight and passenger trains. Demand for rail services continues to grow, and the upgrade of this line is an important project to help meet that demand.
“We thank the local community, particularly businesses, for their patience and understanding.”
Phases one and three of the £280 million government-funded project saw work between Sleaford and Gainsborough completed earlier this year.
Phase two – between Gainsborough and Doncaster – is about to begin, while phase five – between Spalding and Peterborough – will take place in late October.
The ongoing work has drawn criticism from angry drivers who have been forced to alter their routes.
Reader Nichola Baxter said: “Where I wanted to go was just past the railway, but diversions were taking me out to Peterborough... they need to rethink the diversion.”