The works at Birmingham New Street station were due to be completed by Saturday but were still being completed after the planned completion time had passed.
It meant that passengers were left looking for alternative travel arrangements from Birmingham New Street as services were either cancelled or delayed.
The works affected West Coast Mainline and London Northwestern services from and to Wolverhampton, West Midlands Railway services towards Rugeley Trent Valley, Cannock and Walsall, Transport for Wales services to Shrewsbury and Mid-Wales, and other services for Cross Country.
Travellers were able to use National Express West Midlands and Metro services, which were accepting tickets from cancelled rail services.
A spokesman for West Midlands Railway said: “There are cancellations to services at Birmingham New Street, due to engineering works not being finished on time at Birmingham New Street.
“Train services running through this station may be cancelled or delayed and disruption is expected to last until around 1pm today (06 February).
“Currently, we have not requested Rail Replacement transport, as passengers can currently reach destinations on the route by public transport alternatives.
“We will monitor this situation as the incident develops.
“National Express West Midlands will accept tickets on all routes from Birmingham until further notice and the Metro will also accept our tickets from Bull Street to Wolverhampton in both directions.”