I think the HSE▸ would have something to say if anyone suggested a new build of slam door stock even with CDL▸ .
Many a true word is spoken in jest ...
Suggestion - a new build of 3 car d.m.u.s, top speed 80 m.p.h, allowed to carry passengers only on lines where speeds in excess of 100 m.p.h were not permitted. Slam door, single glazed, no a/c but top opening windows. Sturdy but effective materials ... groups of 4 seats around tables. Similarities to previous generations not entirely co-incidental (noting posts here that loco-and-coaches suprises people but they find them more comfortable).
With the "100 m.p.h." stipulation, you're looking at a build that will allow longer trains, hopefully much cheaper per carriage. Services your could run with them ... west of Exeter, Exmouth to Barnstaple, Portishead to Severn Beach and Thornbury, Chippenham to Southampton or Waterloo via Salisbury, Cardiff Valleys, West of Swansea ...
