From the 1970s on the “High Speed” push-pull Edinburgh-Glasgow :
Usage of Class 25s was described from time to time in magazines, but I only ever saw it once, likewise once a Class 37 substitute. It was not apparent how these could operate "as is", whereas the Class 27 had to have modifications for the service; 24 of these were done, 12 27/1 and 12 27/2, and trains operated with one of each type. While the remaining unconverted class 27/0 were always prominent all around Scotland, on Glasgow-Dundee trains, on the West Highland line, down in Ayrshire, on freight, and even as the Glasgow Queen Street banker (still being done in the 1970s for Aberdeen etc expresses) the surplus push-pull locos, which there appear to have been plenty of, rarely turned up elsewhere.
The service had been operated by Swindon-built multiple units from 1956, until changed over at the May 1971 timetable change. The dmus were claimed to be life-expired, and indeed never worked again, being dumped in the Up side sidings at Polmadie, and still lying there, covered in snow, in early 1974. They had been the last major group of 79xxx numbered dmus in service. I’m not sure why they were life-expired when the Swindon-built units for the WR that followed them off the production line lasted for another 20 years.
The "new" rolling stock was early Mk 2, secondhand from the LMR West Coast Main Line. They were not the most suitable. This early batch had been vacuum brake only, and as air braking was required to get the Edinburgh-Glasgow performance, with high speeds into stations, they had to be expensively converted at St Rollox carriage works. They were also dual heated, but the locomotives were initially steam heat only. After a couple of years the 27/2 class was created, which were the last 12 27/1 locos further modified with an ETH supply, not from the main generator but from a separate auxiliary diesel engine. These were very noisy from outside (it was always apparent when they were in operation), unreliable, and had a tendency to overheat, or in the worst cases catch fire, especially if they were at the trailing end away from the supervision of the crew. Of course, additional fire warnings and automatic extinguishers were provided, and these brought along further unreliability of their own, while as the ETH equipment on the coaches hadn't been used for a couple of years, they gave an interesting variety of burning smells and short circuits in their own right once activated again.
The formation was 4SO, FK, BSO. It would have been better if the brake vehicle had been a BFK, along with 5 SO, but there were none available, and really the service just merited being one class only. The First Class was one of my principal criticisms, because it was invariably empty of “real” first class revenue passengers. What it did provide was some sort of private members club for Scottish Region management staff entitled, in those days, to first class free passes, a number of whom commuted daily both ways between Edinburgh and Glasgow, and who sat in pleasant comfort while the rest of the rush hour trains had standing passengers in the other 4 1/2 coaches. The only other regulars were an occasional Scottish Office senior civil servant, entitled by their job grade to first class, but by the terms of the old bulk-purchase agreement between the civil service and BR, it didn’t give any additional revenue. Certainly no Scottish business traveller I ever met wastedmoney on this. A comment just a few years ago by Alan Williams in ‘Modern Railways’ about the current class 170 service on the route, where he described how current equivalent management staff let themselves into evening peak hour trains standing with doors closed through the guard’s compartment, and took all the best window seats in the small First Class compartment before any paying passengers were admitted, showed the tradition died hard.
Also there were odd substitutions of a Met-Cam 3-car dmu, which as you can imagine didn't go down too well. Once, on the 10.00 nonstop from Queen Street, passengers were admitted to an empty platform, and the inbound dmu from Edinburgh, the 09.00 from there, turned up just moments before departure time, 15 minutes down. I don't know why the High Speed spare set was not used, but we all piled in to the Met Cam. Sat all squashed into a 3-car dmu gave the nearest thing in those days to experiencing what life was going to be like 40 years later on the Class 170s with equivalent formations on the route. You were lucky on a fully-loaded Met-Cam to be doing 25 mph by the top of Cowlairs bank, and of course there was a good audience for the crew (the loco-hauled service was of course two-man, in those days, so we had a fireman in the dmu cab) from behind the glass screen. Passing Cadder yard at about 55-60 mph, there was a double yellow in the distance, and the driver not only shut off but started to brake. I think if he’d left the brake on we could have easily stopped at the double yellow, but it cleared to green and we were off again, getting up to 70 mph maybe 10 minutes later. It was way after 11.00 when I got off at Haymarket, so I didn’t see how the next stage of the diagram was handled.
The loco crews were divided equally between Haymarket and Eastfield, two very different groups. Haymarket men had a long tradition of express running, and regarded themselves as the aristocrats of the road, whereas Eastfield was a depot very much from the rougher end of Glasgow, around Springburn, with a background of hard winter nights running on the West Highland and much freight, who regarded the Edinburgh sets as a stuck-up lot, a microcosm of the general attitude between inhabitants of the two cities which amused this Somerset lad at the time. Certainly from their standard of presentation of uniform clothing as they walked towards you, you could often identify whether a crew were from Haymarket or Eastfield before they spoke, with their notably different accents. But if you wanted a hard-hammering run, go for a Glasgow crew. I was once told the best run of the day was always on the 20.30 from Edinburgh, an Eastfield turn, into Queen Street at 21.15 in the days when Scottish pubs closed at 22.00, and extra minutes after booking-off time were precious. Crews said the Class 27s were driven as much on the ammeter gauge limit from the generator as the speedometer. They had long been driven this way on the West Highland gradients, but of course at nothing like the speeds.
The Class 37 substitute, eastbound, described above was certainly one of the "belter" rides I had where the 90 mph limit was evidently treated somewhat laxly and the train in the latter half of the journey would be pretty much up at 100 mph,. This was a regular and enjoyable feature of the route; bear in mind that initially it still had semaphore signalling in part. You couldn't really do it if on time, because the service at both ends came in just after the dmu stopper on the same tracks, but if there was a slightly late departure then there was a chance. The crews knew their signal sightings and what they were doing, although I recall one near-miss Haymarket arrival where I'm sure we were still doing 75 mph past the loco depot, with the brakes absolutely hard on, and finally came to a bumpy stand right at the east end of Haymarket platform with the loco off the ramp. I had a mental vision that the driver, from 100 mph full power, had suddenly shut off and slammed the brake hard on, then folded his arms, touched nothing, and sat there until we stopped, turning to the fireman and saying “beat that”. Interesting times, from long ago and far away.