A major change to timetables across Britain takes effect on Sunday, adding 1,000 new weekly services as well as the first non-stop journey between London and Bristol in decades.
The alterations follow new investment to rail infrastructure as well as upgrades to carriages.
According to Industry body the Rail Delivery Group (RDG), the new timetable means that 5,000 new weekly services will have been brought in over the past two years.
A change to the timetables back in May 2018 left services in the North and South East crippled and passengers angry with Network Rail, the train operators, and the government.
Anthony Smith, the chief executive of passenger watchdog Transport Focus, said: “This time around passengers need the rail industry to deliver a smooth set of timetable improvements – so they can reliably use both new and existing services.
“Many passengers should have a greater choice of services with more seats as result of these changes. However, there will also be some who lose out with fewer or slower services.
“Train companies must have plenty of visible staff on hand to guide passengers, to answer questions on how these changes will affect them, and to explain what travel choices they have.”
The RDG has attempted to address these fears, claiming that “years of work” has gone into “drafting, consulting and planning for these changes”.
Robert Nisbet, a director at the industry body, urged passengers to check whether any of their regular journeys are affected by the timetable changes.
“Train operators and Network Rail will be working together to run a reliable service and respond quickly to any teething problems as people get used to the change.”
The changes will be the biggest for the Great Western Railway network since the 1970s thanks to the electrification of the Network Rail line between London and Bristol.
The new intercity express trains between London Paddington and Bristol Parkway could complete their journeys in one hour and eight minutes, 12 minutes quicker than the current fastest services.
Journeys from London to Bristol Temple Meads near the centre of the city will be cut by 17 minutes to one hour 19 minutes, and trains will be more frequent – with three instead of two running during the morning and evening peaks.
ScotRail will also receive improvements, with services added to north-east Scotland and additional seats on journeys between Edinburgh and Glasgow.
A new station in north-east Glasow, Robroyston, will be opened on the line between Queen Street and Cumbernauld.
Other operators introducing new services are Greater Anglia, London North Eastern Railway, Northern, TfL Rail, Thameslink, Transpennine Express (TPE), Transport for Wales, West Midlands Railway and London Northwestern Railway.
TPE admitted last week that the frequency of its new direct Liverpool-Edinburgh trains will initially be lower than the planned hourly service.
The firm blamed a maintenance backlog and infrastructure problems for delaying crew training, as well as the late delivery of new trains.