It's not often I can answer queries on old Triang Hornby stuff but I just happen to have catalogues 13 to 20 as I have never disposed of them.
The set you mention RS90 appears in edition 15 on page 4. The description is as follows:-
"Pullman Express Train Set. Contains "Albert Hall" Express Locomotive, three Pullman coaches and Large Oval of track complete with level crossing and automatic uncoupler".
The image shows the locomotive with a BR late totem on the tender.
The set does not appear in editions 14 or 16.
"Albert Hall" in BR green is also available separately as R579. It also appears in pictures on page 22 - in the through station R5083; page 24-25 "signals and bridges" and page 25 on the turntable (wish the current model was like this one
) In all cases the loco is BR green.
Edition 14 (the previous year) has "Albert Hall" as R579 in BR green and features in the overall photo of the steam locomotives available.
Edition 16 has "Albert Hall" as R759G in Great Western livery. 3 additional names are included in the box. The catalogue says the loco will consume 350mA and mine has a price of 82/6 (£4 - 13 to anyone under 38 and it looks like they were keeping the 1/2 too!)
Edition 16 also introduced System 6 track.
So you are correct about the set only being available for a year. My catalogue shows the loco being in BR livery. The following catalogue shows the locomotive has changed to GWR.
The most likely explanation for the difference is that your original set was a "late" one by which time supplies of the BR liveried loco had dried up to be replaced by the GWR version.
No doubt someone with one of the Rovex history books will have a fuller explanation.
David
The set you mention RS90 appears in edition 15 on page 4. The description is as follows:-
"Pullman Express Train Set. Contains "Albert Hall" Express Locomotive, three Pullman coaches and Large Oval of track complete with level crossing and automatic uncoupler".
The image shows the locomotive with a BR late totem on the tender.
The set does not appear in editions 14 or 16.
"Albert Hall" in BR green is also available separately as R579. It also appears in pictures on page 22 - in the through station R5083; page 24-25 "signals and bridges" and page 25 on the turntable (wish the current model was like this one

Edition 14 (the previous year) has "Albert Hall" as R579 in BR green and features in the overall photo of the steam locomotives available.
Edition 16 has "Albert Hall" as R759G in Great Western livery. 3 additional names are included in the box. The catalogue says the loco will consume 350mA and mine has a price of 82/6 (£4 - 13 to anyone under 38 and it looks like they were keeping the 1/2 too!)
Edition 16 also introduced System 6 track.
So you are correct about the set only being available for a year. My catalogue shows the loco being in BR livery. The following catalogue shows the locomotive has changed to GWR.
The most likely explanation for the difference is that your original set was a "late" one by which time supplies of the BR liveried loco had dried up to be replaced by the GWR version.
No doubt someone with one of the Rovex history books will have a fuller explanation.
David