Mark 2/2a BFK/BSK/BSO - external differences?

[Rhydgaled]

According to this Rail UK topic, no mark 2 BSK vehicles were built, yet I am seeing some pre-owned Hornby mark 2 BSK models advertised for sale. This archived RMWeb topic suggests that Hornby's mark 2 was actually more dimensionally-accurate than Bachmann's mark 2a (so, side-question, why does Bachmann's look right to me in photos and Hornby's looks wrong - is it just the paint job (eg. awful chrome window frames on Hornby's)?), with the Bachmann BFK also having incorrect roof vents while Hornby, apparently, got it right.

 

However, I'm struggling to 'spot the difference' between the exteriors of the BFK/BSK/BSO coach diagrams in the diagram book I stumbled across (BRB Vehicle Diagram Book 200, I think from this page). So, somebody please let me know if there are any physical external differences between those coaches? I'm most interested in the Mark 2 BFK vs BSK question, since if they were the same the Hornby (fictious?) BSK could be made into an (accurate) BFK simply by repainting with a yellow stripe to indicate first class.

[SRman]

There were no Mark 2/2A BSKs built: all were BFKs, but some were later downgraded to second class. 

I'm not sure about the accuracy of the sides, but certainly Bachmann have the better underframe details. Mark2s (described as 2Z in most later publications) were originally vacuum braked and steam heated, whereas Mark 2As were air or dual braked and electrically heated, but some Mark 2s were upgraded to air and electric later, particularly those on the Southern Region. 

The earliest Mark 2s were FKs and finished in maroon or green, and used in steam hauled trains. Bachmann have modelled some of these, correctly with the mark 1 window vents and gangway styles.

 

 

Edited March 16, 2023 by SRman
Fix minor grammatical error.

[BernardTPM]

The Mk.2/2A BSO shared the same shell, but had an open interior with 31 seats as one seat was lost at the outer end due to the offset width of the toilet compartment (as shown in the BR diagrams, p69). Externally there were less and differently spaced roof vents over the passenger area. Interestingly the BR diagram shows the roof vents for the BSO on the BFK version too! Don't be fooled by that, the Hornby pattern is correct for the BFK (and for the BFK downgraded to BSK).

[Wickham Green too]

13 hours ago, Rhydgaled said:

... the Hornby (fictious?) BSK could be made into an (accurate) BFK simply by repainting with a yellow stripe to indicate first class.

BSKs ( or BSOs ) and BFKs wold have had different number series, of course.

[BernardTPM]

And the BFK numbers were altered in the mid-'80s from 14xxx to 17xxx series.

[andyman7]

13 hours ago, SRman said:

There were no Mark 2/2A BSKs built: all were BFKs, but some were later downgraded to second class. 

I'm not sure about the accuracy of the sides, but certainly Bachmann have the better underframe details. Mark2s (described as 2Z in most later publications) were originally vacuum braked and steam heated, whereas Mark 2As were air or dual braked and electrically heated, but some Mark 2s were upgraded to air and electric later, particularly those on the Southern Region. 

The earliest Mark 2s were FKs and finished in maroon or green, and used in steam hauled trains. Bachmann have modelled some of these, correctly with the mark 1 window vents and gangway styles.

 

 

 

The Hornby model was introduced by Triang-Hornby in 1968 as a BFK which it is correct for. From 1973 (as the rebranded 'Hornby Railways') the first class markings were removed and it therefore (incorrectly) represented a BSK - although as noted above, Real Life caught up in the late 80s when some of the real vehicles were declassified.

Bachmann also model the BFK but unfortunately used works drawings with the roof vents in the wrong place. Although the model is 'fine detail' - it is wrong in this regard whereas the Triang-Hornby model is correct. Bachmann do make the BSO which is correct, the roof vents reflecting and open saloon layout.

[hexagon789]

20 hours ago, SRman said:

whereas Mark 2As were air or dual braked and electrically heated

2As were air brake only and dual heated as built. Some were later converted to vacuum braking but there were no dual braked Mk2s of any variant.

 

All Mk2s up to and including C were dual heat.