The South Wales Mainline (Bristol-Swansea) (Locomotives Class 800s Class 153s Class 66 Class 60 Class 175s) (DLC Carmarthen Expansion Or Milford Haven Class 56 Class 67 ETC
Short suggestions with barely any information like this really makes me yearn the days on this suggestion forum when we had the how to and not to write a suggestion thread pinned at the very top of the forum. As without it short suggestions like these become more common unfortunately. Also to the OP details like mileage, country, interest reasoning etc are all what make a suggestion great. Next time try looking at suggestions by some well-known poster which have great suggestion I used for some of my TSW suggestions such as elarthur, edward#5859, trainsimplayer, TrainGeek08 and etc.