Govia Thameslink Railway (GTR) is advising passengers to plan ahead for the biggest timetable shake-up in UK rail history.
GTR has published the new details of train services on the RailPlan 2020 website and it will affect most passengers who travel to and from Harlington, Leagrave, Luton and Luton Airport Parkway.
The new schedule will operate from 2am on Sunday, May 20, and passengers are being advised of a two-week transition period to make the necessary changes to trains, services and drivers.
Many train carriages must be relocated across the network; at the same time the network needs to continue to run services, which is not feasible in one weekend or overnight. There are also changes to the formation of existing trains as they move towards providing longer trains.
During the transition period there may be a reduced number of trains.
While there will be more services, longer trains and thousands more seats, between Luton and London for the first week there will be one less train running in the morning peak time and two less trains running during the evening peak time, for the following two weeks it will be one less train during the evening and no changes to the morning.
The full service will run across all routes from June 11.
The changes to the Thameslink service include introducing 115 new trains and an increase in frequency and length of trains between Bedford and St Pancras, at Luton 27% more carriages and 25% more seats.
Passengers are advised to check the new timetables on the RailPlan 2020 website.
Charles Horton, GTR chief executive, said: “A huge number of passengers will notice the benefits in terms of new journeys, better intervals between trains, improved reliability, and more capacity across a wide region.
“We are redeploying trains and crew and there may be some disruption, so we ask passengers for their understanding during the transition period of several weeks during which time a very small number of trains will not run. Almost a quarter of all rail journeys are taken on the GTR network and because of the necessary scale of the change we strongly urge passengers to check ahead as to how their journeys will be affected.
“Introduction of the new timetables is a major milestone in the delivery of RailPlan 20/20, our programme to modernise rail services, taking advantage of the new infrastructure and trains provided by the Thameslink Programme.”