Given the discussion on the SWR Class 442 thread about gauge clearance issues, where even though the units operated on the South Western for nearly twenty years they are being treated as new units, the same will appply if Mk 4 stock is used anywhere other than the WCML. Now TfW and Arriva are happy to get the necessary work done with Network Rail for their Welsh and WCML services. But realistically is anyone else going to be interested in taking on Mk 4 stock? The only potential operator would be Chiltern to replace their Mk 3 stock, but I could only see them doing that if someone else wanted a small fleet of plug door fitted Mk3 LHCS.