Rail passengers were being urged to plan ahead for engineering work which will affect weekend journeys.

Network Rail said the work on the Midland Mainline, which takes place on six consecutive weekends from 21 June, will result in "significant improvements".

Intercity services will be diverted between Kettering in Northamptonshire, and Leicester, extending journey times by 45 minutes.

The project involved work to make progress on a new phase of electrification, which would allow greener "bi-mode" trains to be introduced. There would also be upgrades to the track, signal and communications equipment and drainage systems.

The firm, which owns most of the UK^▸ (United Kingdom)'s rail network, added that the project's benefits would include "making the line more resilient and benefitting train performance". The work programme included lowering sections of track to accommodate overhead line equipment without the need to demolish and rebuild bridges.

Network Rail said this would enable a new phase of electrification to take place between Wigston in Leicestershire and East Midlands Parkway, paving the way for a greener fleet of bi-mode trains to be introduced.

East Midlands Railway, which runs through Corby, Kettering and Wellingborough, will operate an amended timetable and trains will not call at Market Harborough. A connecting rail replacement bus service will operate between Kettering and Leicester, calling at Market Harborough. Additional services will be provided on Sundays for passengers travelling by Grantham.

Philippa Cresswell, the customer experience director for East Midlands Railway, said: "We recommend customers planning to travel to or from London over six weekends between Saturday 21 June and Sunday 27 July to check their journey in advance of travelling. We would like to thank our customers for their patience whilst Network Rail upgrade the overhead power lines to enable our bi-mode trains to run on our Intercity route in the future. This work will greatly benefit our customers with more reliable journeys to and from London."