Journey times between Cardiff and London could be cut by 20 minutes if plans for a new service get the go ahead.
Grand Union Trains want to introduce the new service by the end of next year.
The proposed service, which would start operating late 2020, would run from Cardiff Central to Newport, Severn Tunnel Junction and Bristol Parkway, then express to London Paddington. It will also stop at Cardiff Parkway when it opens.
The new service is also expected to create around 135 new and permanent full-time jobs, most of which will be based in South Wales.
The company say they'll offer passengers a 50% discount on their ticket if they're unable to find a seat on the proposed new service.
Under track access rules, other rail operators are able to provide a service if a route is not deemed congested, and the Office of Rail and Road (ORR) approves an application. The application will now be subject to a 28 day consultation period before it is forwarded to the ORR.