Services on the electrified Merseyrail network are operated by British Rail Class 507 and Class 508 electric multiple unit trains (EMUs). These replaced pre-war Class 502 (originally constructed by the LMS) and similar Class 503 EMUs. There are 57 trains in service on the network. There are 2 lines northen and wirral. At one end of the lines us Southport and they both go there, the northern line goes around the Liverpool Central Station circle including lime Street, Moorfields, James Street and Liverpool Central and the most common way it goes is to hunts cross. It also goes to kirby and Ormskirk. The wirral line goes from chester to the central circle. It also goes to Ellesmere port, New Brighton, Bidston and west kirby.
This would be a bit of a easy win for DTG, 507/508 are very similar to the 313/314, either of the two routes are not particularly long, and have tunnel sections where scenery would be minimal
To be fair I wouldn't be surprised if both lines were possible In the close future, considering the tunnels reducing scenery constraints and the re-use of the trains - freeing up Dev time.
The question is, would you prefer the Wirral line or the Northern line? I doubt both would be viable in the same DLC. Personally I think the Wirral line would be most interesting, having a one-way system loop through tunnels under the Mersey and around Liverpool city centre, before continuing back along one of four branches to the suburbs on the Wirral, allowing a return journey without switching cabs.
I would prefer to see the whole network as one DLC, even if this costs more than the usual £24.99. If only one of the lines were possible, I’d definitely say the Wirral Line.