Plans have been unveiled by rail operator Transport for Wales for more trains, more space and better facilities from December.
TfW says the plans will provide capacity for a further 6,500 commuters every week on its network.
In November last year, the operator apologised for a number of delays and cancellations to its train services.
TfW and Network Rail admitted then that passengers "deserve better" after it issued a written apology to customers saying they "haven’t received the service they "deserve and expect”.
Now, Transport for Wales says Valley lines will, from December, have four-carriage trains on peak services.
It also says passengers between Cheltenham and Maesteg, and between Cardiff and Ebbw Vale will have access to modern Class 170 trains with more space, onboard passenger information systems, accessible toilets, air conditioning, Wi-Fi and power sockets.
Mandatory requirements for rolling stock to meet modern accessibility standards comes in to force on 1 January 2020.
Our customer research reveals that being able to sit or stand comfortably on a train is a top priority for many people, and therefore we hope that our customers will welcome plans which will mean a big increase in capacity for December.
TfW took over the Wales and Border Franchise from Arriva Trains Wales in October 2018.