For those that don't know, Ellis Clark have been building a reputation with their O scale items and have now announced their first OO product. £325 per set of 4, with 3 livery choices. Just the job for those widened lines layouts. (I have 2 sets of Ian Kirk ones that I bought at reasonable prices way back so now face a dilemma!)
One of these survived long enough to enter preservation and sometimes carries passengers on the North Norfolk Railway. I've been on it!
From what I've read some batches of these loco-hauled coaches built by the Great Northern Railway (GNR) for routes in north London were designed for easy conversion to electric traction.
However, whilst the Met Railway did electrify some passenger sets that were originally built for loco haulage, the GNR did not do likewise. Had it done so then the routes to Edgware / High Barnet / Ally Pally (all via Highgate) would likely still be main line operated today.
I suppose that these could be run alongside 1938ts tube trains, depicting the early 1940s transition period on the Northern line - or alongside Metropolitan Railway and even Great Western Railway (City Stock) trains on the Widened Lines route between Kings Cross and Moorgate.
I've just cleared out a late friend's railway collection and there's a couple of part-built quad Art sets in there if anyone's interested. The bodies have been built but not painted. all bogies and details are there to finish the job. PM me if interested.