Wickham Green too

Looks more L.N.W.R. to me - no roof dome and local to Wolverton, too

BR weren't very good at building things in numerical order ......... the last 9F should have been Crewe's 92250, for instance.

The answer will be in https://hmrs.org.uk/southern-style-part-one-london-south-western-railway.html .......

The 'Scottish' variant of the 'K' type Pullman varied from that modelled by Hornby in having British Standard gangways and screw couplings - and a noticeably different window layout. The Heacham Car could have been 'Montana' an earlier vehicle very similar to Hornby's twelve-wheeled Parlour First - but mounted on four-wheeled 'American' bogies : originally a 'Guard Parlour' Car for the S.E.C.R. .......... IF this is the Car in question, it was moved to Barnwell Junction where it stayed for many years .... .... before preservation at Petworth. ( It gained standard

Crikey - that's FOUR Airfix kits stuck together !

...... though it does look a little more 'orange' than the earlier Car to the left !

There were plenty of mines served by narrow gauge railways - rather than internal systems ......... but not a lot of them were coal mines !

The body screws are just behind the buffer beams - as shown in the fourth post on this page !

Might your layout be set in the first half of the 20th century by any chance ??

Or they might open a branch this side of the Tamar to circumvent any such problems ...................... c'mon, they've thought of that already !

The former L.B.S.C.R. arc-roofed stock was also too wide to run on the S.E.D. - but the Southern saw fit to modify or remove the duckets so they were OK ...... could that not have ben done to the L.S.W.R. sets too ?

The Southern Railway initially standardised on what is probably best known as 'Maunsell' green - though often described by assorted, inaccurate, vegetable names. Just prior to the war a brighter green was introduced called 'malachite' .... both these could be described as SR greens. Both colours were in evidence well into the British Railways period - often with updated insignia - until 'crimson' ( also known by innumerable other names ) covered all. In 1956 the Regions were given the freedom to paint rolling stock as they wished and the Southern Region - also 'SR' - adopted a ( darker )

Indeed, all the three-coach 'birdcage' sets were considered to be 'Rover' sets as they could - and did - rove around the Eastern and Central Sections. [ I've never figured out why the Western Section was excluded - simply because the native brakes were wider over duckets and couldn't be included in a common fleet, perhaps.]

I remember when you got two hundred an' forty d to the quid !

They certainly would have been visible when in-situ ..... I have no doubt there are people watching who could give you chapter and verse, but I'd guess the top would have been at or about sleeper level ( having tripped over a few in the past, that's my impression anyway ). The use of a metal insert would have been to permit a finer groove than available with concrete. Monuments would generally have been used on curves - though I guess anywhere else with a history of movement might hae beem marked ...... the alignment would have been checked and corrected by slewing by hand in the early days -