One At Each End.
By Nick Lawford.
During 1970 the Scottish Region received the go ahead for service and route improvements between Glasgow and Edinburgh. £1.5 million was allocated to upgrade the Intercity service to head off expected motorway competition. On completion of the M8 between the two cities a one hour centre to centre road journey would be possible - and for which the local bus operators had already applied for 70 mph express licences.
The route via Falkirk had been diesel operated from 1957 when six car 'InterCity' DMUs (Diesel Multiple Units) were introduced. The line sustained a traffic growth of 7% per annum - double that averaged by most Intercity routes - and an increase in market share from 42 to 59% over ten years. 80% of all journeys were end to end with well balanced two way flows. On contemporary Intercity ranking, total passenger journeys were second only to London to Brighton.
After modest service accelerations in 1966, trains were scheduled 55 min eastbound and 56 min westbound, calling at Falkirk High and Haymarket only, or with a 70-71 min timing calling Lenzie, Croy, Falkirk Grahamston, Polmont, Linlithgow and Haymarket. But the DMUs were restricted to 75 mph maximum and, though having a book life of several more years, lagged well behind in terms of InterCity passenger comfort levels.
DMU operation had commenced in January 1957 using a dedicated fleet of 31 motors and 15 trailers. By 1966, the motors normally in use were based at Leith Central from the batches 79083-79111 and 79155-79168, with trailer buffets 79440-79447 and trailer firsts 79470-79483. 79091-94/96-111 had full width driving cabs without no corridor connections with the other motors were gangway fitted. All were "White Circle" coupling code but were otherwise conventional sets with AEC-BUT engines - 600 hp from four engines in each three car set. The ScR (Scottish Region) was aiming for a 45 min schedule with two intermediate stops. In 1965, some consideration had been given to either uprating or replacing the power units.
Turbines for rail traction probably had more to do with Rolls Royce and BRs Technical Centre both being located in Derby rather than any practical consideration. At that period, the aircraft industry was promoting aviation turbines for other uses, and a 1500 hp turbine powered, InterCity multiple unit based on the AM10 EMU (Electric Multiple Unit) bodyshell was proposed. The turbine express unit, and the idea of installing one "Dart" engine (as used on the Vickers Viscount turbo-prop) into stretched Brush Type 4 bodyshells, were never progressed into reality.
Detailed planning of a more practical nature started in Glasgow in 1968. Using a basic definition of 90 mph operation, rolling stock of minimum contemporary Mk.2 interior standard, a 30 minute interval service Glasgow Queen Street to Edinburgh Waverley was set, alternating non-stop to Haymarket and one intermediate call at Falkirk High. Routine permanent way renewal had already upgraded track standard (but not line limits) to 90 or 100 mph. There were no significant grades except for the 1 in 45 incline out of Glasgow Queen St to Cowlairs. The main limitation on route speed was on signalling. At the time 75 mph was blanket maximum speed in Scotland and resignalling was necessary to increase braking distances to allow 90 mph running. £ 600,000 million was allocated to Cadder - Greenhill Jn - Falkirk area resignalling and just £ 200,000 for track work.
Scottish Region proposed ETH (Electric Train Heat) equipped Type 4 traction, but such machinery was then in heavy demand elsewhere. The only appropriate Class 47 and 50 machines were urgently needed for introduction of new Mk.2D air conditioned stock on long distance routes, and their respective operators were not willing to release them for short distance six coach loads. Only small locomotives from ScR own fleet could be spared. Power would be provided by two Type 2s to give 2500 hp and for 90 mph running only class 25 and 27 would be suitable. Push pull working with one locomotive at each end connected by multicore cable running through the coaches would ease terminal times, eliminate engine changing, and also circumvent the need to develop and convert push-pull driving trailers.
Timings for the proposed service had been established in 1968 trials. Early that year push-pull tests were carried out between Doncaster, Peterborough and Pyewipe using nine Mk.1s, and converted BSK (Brake Corridor Second) driving trailer powered by a 37 or 47. The set moved to Scotland with testing starting late February, and high speed trials on Sundays through April. On the first two dates a Type 3 was tested on five and six coach sets, running end to end over the 47.25 mile route in 40.5 min at speeds of up to 105 mph. On the third Sunday, Type 4 trials, a 47 should have been used but a last minute failure prevented the use of the test train, and a Class 50 and six AB were substituted and hauled conventionally each way - the 50 was not planned for testing on this date. Local newspapers claimed the reported 109 mph achieved was with "Kestrel" which certainly was not the case.
The ScR tested several permutations of stops and set 42 min for Haymarket only; 49 min Haymarket, Linlithgow, Lenzie; 50 min Haymarket, Falkirk Grahamston; 62.5 min Haymarket, Linlithgow, Polmont, Falkirk Grahamston, Croy, Lenzie; and 58 min Haymarket, Linlithgow, Polmont, Falkirk High, Croy, Lenzie; returning in 41.5, 49, 49.5, 62, and 57 min. It is important to note these test runs were to acquire timing data only - not to prove push-pull working.
£ 500,000 was allocated for the modifications to twelve locomotives and thirty six coaches. Twelve 27s had already been authorised for ETH conversion in mid 1969. Delivery of Mk2C stock to the LMR (London Midland Region) would release older vacuum braked Mk.2s. Principal modifications were fitting air operated disc brakes - the first regular use of disc braking on locomotive operated stock - and enhancements to the pressure ventilation system to bring the stock into line with Mk.2C heating levels. Dual heating was retained.
The original plan was for trains formed DL-BSO-SO-FK-SO-SO-SO-DL (DL= Diesel Locomotive, BSO = Brake Open Second, FK = Corridor First, SO = Open Second) giving a capacity of 287 second and 42 first class seats at 191 or 192 tons tare load. The actual vehicles transferred for service start up were TSO (Tourist Open Second) 5126/30/34/37/42/44/46/47/52/53/60/69/76/82/85/87/89/90/92/95/97, 5202, BSO 9387/95/97, 9400/03/11/12, FK 13411/15/16/23/24/27/31 which on conversion were marked "Edinburgh - Glasgow Service only" on coach ends. No catering cars were provided - the DMU buffets were reported as popular with travellers but loss making.
Several test and training runs were made from early 1971 and 5404/5407 performed between Derby and Leicester on a full disc brake set around mid March. In Scotland testing pathways were at 10:18 13:18 16:18 19:18 from Edinburgh Waverley and 11:20 14:20 17:20 20:20 from Glasgow Queen Street although the third run was to/from Cowlairs only. Testing started on 22nd March with 5403/5413 and 5404/5413 used on 24th and 26th. 5404/5413 were used on 25th on a press and demonstration run.
The new service started with the timetable change on 3rd May 1971 - with departures from both Edinburgh and Glasgow at xx:00 and xx:30 - alternately calling at Haymarket (43 min timing) only, with the xx:30 also calling Falkirk High (45 min) while a recast DMU service served other stations. The fast trains were timed end to end at an average 66 mph. There were five daily rolling stock circuits with four starting and finishing at the Edinburgh end and one stabling overnight at the Glasgow end.
The first dedicated apparatus was based at Haymarket - 5374/91/92/93, 5403/04/07/08/09/11/12/13. All twelve had been modified and overhauled, including traction motor armature rewind, September 1970. These were the first dual braked 27s, and locally had been expected to appear in blue and grey livery painted to match the stock.
The push-pull modifications included automatic fire detection for use on the locomotive at the remote end of the train and "clear call" driver guard communication. These alterations were not as extensive as those applied to the Southern Regions 33/1s - presumably the 27s did not require buck-eye couplings and rubbing plates as a locomotive at each end would balance drawbar forces, and there were none of the complex controls associated with operating EMU stock.
The operators obviously had high availability expectations from their small pool of equipment. Programming ten out of a maximum twelve machines to traffic demanded a daily excess of 83% availability. This was rather optimistic considering class 27 had previously returned around 75% and had never before utilised on sustained 90 mph running - never mind over 600 miles a day.
Good forward planning initially kept some of the displaced DMUs on standby for the service - with one set at Waverley, one at Cowlairs and two further held in reserve at Leith Central depot. It was good planning as traction was to prove troublesome in the early days. Late running also meant to frequent stepping back of sets - using a DMU to make one return trip to reset the stock pattern. At times the operators resorted to multiple units for the basic service - but usually the DMUs were taken out of service as soon as alternative locomotives could be found. Single locomotive working was actually more difficult to provide since turnover engines would be needed at each end meaning three locomotives for one set whereas only two were needed under push-pull.
Almost as soon as the service started various 25s and 37s substituted for 27s. Air braking requirements limited the choice of alternative power - with the only other dual braked 27s in May 1971 were Eastfields 5386 and 5410. Usual formations were 27/37 or 27/25 with 6844, 6857, 6936 and 7578, 7581 in regular use almost immediately - and appearances from 6837/41/46 and 6903. By mid-May 37/37 were not unusual but 25/25 were less common. It is interesting to note that throughout the entire reign of push-pull 27s on this route that any substitute locomotive invariably came from either Eastfields or Haymarkets allocation - rarely from other sheds.
It seems that into late 1971 and early 1972 the service had settled into routine 27/27 operation - not through an increase in reliability of the 27s themselves but because more air braked and push pull fitted locomotives were in traffic - with 5387/94/99 available from June 1971 joined by 5380/88/97 and 5400/01 in 1972 - and all based at Eastfield rather than Haymarket. Running however was still erratic - through June 1972 of 362 trains recorded at Falkirk High although 127 were on time or one minute early most of the other 235 were more than five minutes late.
The twelve 27s which had been authorised in late 1969 for ETH fitting had been expected to be from the 5403-5415 batch. At least six machines from this group - 5404/07/08/09/11/13 - were recorded as modified to "boiler fitted" from 12/70 to 05/71. The original plan was to provide six with boilers and six no boiler from Derby, and twelve more routine overhauls following from Glasgow works with operational boilers. Unfortunately Diagram Book information regarding class 27 in this period is inaccurate - at one point even the later 27/2 were not recognised as ETH. It is possible that the six 27s were de-boilered then re-boilered. The twelve Derby overhauls were fitted with dummy ETH sockets but no cabling, although one time intention was to tap ETH off the main generator. One or two locomotives were reported as tested as such in 1972 but appears to not have been applied in general.
Although rated at 90 mph, 27s had never regularly sustained these operating speeds and problems arose. When the choice of power fell on the Sulzer 6LDA engined Type 2s, 27s were selected over slightly newer 25s because the latter had already shown themselves to be prone to traction motor problems, and sensitive to overheating. Otherwise the newer 25s would probably have made a better choice with the lightweight AEI 253AY traction motor. But problems were soon to arise on the 27s GEC WT459 machines as well.
Early problems were flashovers caused by vibrations from loose brush mountings, loss of commutator covers while running at speed, and problems with traction armature banding. Traction motor suspension arrangements required modification while other mechanical modifications were required to brake gear and primary suspension. A different problem was loose asbestos sheeting in the engine room allowing excessive heat build up to activate fire alarms although there was no actual fire.
In early 1972 serious consideration was given to abandoning push-pull operation, with Scottish Region engineers carrying out further high speed tests with 37s. Overnight runs were made towards the end of March 1972 using three locomotives hauling disc brake sets conventionally - turning over at each end, with the incoming locomotive at Queen Street banking the departing train to Cowlairs as in normal practice. The schedules of 43 min (Haymarket only) and 45 min (Falkirk High and Haymarket) were again maintained. Operating the service this way would entail less locomotives with seven 37s daily in place of ten 27s, but coupling and uncoupling locomotives in the limited terminal time every half an hour was simply not practical and the idea was shelved.
Civil engineers also raised problems associated with such continuous high speed running and unsprung axle loads. Push-pull Class 27 technical reliability was improving by June 1972, but track defects, requiring Sunday diversions through either Dalmeny or Cumbernauld, became necessary solely to rectify problems attributed to 27s themselves. Diversions Winchburgh Jn - Dalmeny - Saughton Jn took place the first two Sundays in September, and Cumbernauld diversions between Cowlairs and Polmont Jn through Cumbernauld and Falkirk Grahamston on the four following Sundays. The latter required reversal at Cowlairs - and in order to maintain the BSO at the buffer stops end of Cowlairs incline all sets were reversed at Millerhill using Niddrie West triangle before and after service.
Contemporary reports from late 1972 suggested that the original twelve modified 27s were still the first choice with another six 27s (5380/87/94/97/99, 5401) and six 25s second choice. The numbers of all suitable machines being reported as 5374/80/86/87/88/91/92/93/94/97/99, 5400/01/03/04/07/08/09/10/11/12/13, 6844/46/57, 6919/37, 7576/78/79/80/81/82/83/84/90/91 - in reality the local allocation of dual braked locos. Of the 25s, some machines may have been temporarily push-pull fitted - probably 7578 and 7590, and possibly 7581 and 7591 - but no diagram was issued to reflect this.
In 1973 5395 and 5396 were dual braked and push-pull fitted - bringing the total modified 27 fleet up to the final twenty four. The 1973 renumbering scheme produced three sub-classes: 27/1 original, 27/2 push-pull and 27/3 push-pull and ETH, with number ranges 27001-27044, 27101-27118 and 27119-27124 respectively. Sub-classes were later amended to 27/0 27/1 and 27/2 but not before 5391 was converted to 27/3 standard at Derby works, deboilered and fitted with auxiliary diesel engine and extended range fuel tanks. The eight cylinder 172 hp Deutz engine drove a Houchin 120 kW generator producing 800 V with ETH index 28 - low in comparison with other ETH locomotives but sufficient for six coach loads.
Before the Deutz diesel engine was adopted, it had been intended to use gas-turbines to drive the ETH alternator. A compact 90 kW gas turbine manufactured by David Budworth Ltd was tested, and was planned for installation in 27119 if it could be developed up to 130 kW. The turbine however was unable to reach either its rated output or efficiency and the project was dropped. This may have been the reason for the delay in introducing ETH to the route - and almost certainly the cause of Derby outshopping 27s with dummy ETH fittings.
Within a year five more - 5391/92, 5403/10/12 - followed to become 27120-27124. The second group of six for similar treatment were to have been 5404/07/08/09/11/13 but renumbering intervened and slightly different machines were selected. 27119-27124 became 27201-27206, and 27113-117 were modified to 27207-27211. 27118 (5413) was not converted but 27103 (5386) became 27212. 27118 then took up number 27103.
27101-27112 were all to Diagram 27-1AX weighing 77.3 tons carrying 685 gallon engine fuel, 100 gallon boiler fuel, 450 gallon boiler water, and 1750 lb/hr Stone boilers. 27201-27212 were all to Diagram 27-2AX weighing 76.8 tons and 970 gallons engine fuel. Strictly, 27101 ought to have had a special Diagram - as built 5374 was from the no boiler batch delivered new to Thornaby, but perhaps the remaining differences after modification were too detailed. The other twenty three were all new to traffic to Leicester and boiler fitted. Locomotive weights compare with 74.5 and 72.3 tons for the original vacuum braked steam heat and no boiler versions - equivalent to Diagrams 27-0AV and 27-0BV.
As a total of 24 locos were available to cover 10 daily diagrams use of other machinery declined, although technical troubles continued especially with traction motors when at one point in 1975 ten locomotives were stopped awaiting replacements. Some problems were also encountered with the auxiliary sets on the 27/2s with both electric generator insulation failures and diesel engine damper failures. One engine also seized caused through hot air recirculation in the engine room. In 1976 traction motor suspension failures reoccurred, followed in 1977 by a new problem of breakages to driving gear wheels. As a precaution all 27/1 and 27/2 were fitted with newly manufactured gears with the originals reused where possible for the 27/0 fleet.
Otherwise 27101-27112 and 27201-27212 plied their way between Glasgow and Edinburgh for nine years and probably offered a higher level of service than credited. In 1979 replacement trains started to appear - but not before February 1979 when over one weekend the 27s were diverted to Glasgow Central through Shotts due to bridge renewal at Castle Cary. Push-pull 47/7 trials did not start until August - the delay in making the Mk.3 stock available was due to the demands of Penmanshiels tunnel diversions and Euston - Edinburgh services. 47/7s started revenue service 22nd October and by December such sets were covering three Mondays-Fridays diagrams. One all day 27 set continued operation into February 1980. The last observed working took place on 3rd April but the locomotives involved have not been recorded.
The disc braked Mk.2 coaches were due for cascade in March 1980 onto the Newcastle-Liverpool service but the Scottish Region retained one set which ran until 1986 (with 47/7 and DBSO) on various workings until 1986. As there was no further use for push-pull 27s, 27101-27112 and 27203-27212 were allocated numbers 27045-27066 in order, 27201 and 27202 already withdrawn with fire damage. 27203/06/07/08 were also withdrawn before acquiring their new numbers.
So a unique service ended. No other push-pull trains have regularly operated on a day in day out basis anywhere on BR with locomotives at each end. The Scottish Region must have evolved its plans to a very tight budget - to plan for ten locomotives in daily traffic when only twelve were available is tight resource use even by todays standards. Despite the technical shortcomings in the earlier days the route sustained 5% traffic growth though the 1970s and the 45 min journey must have been an attraction.
Click HERE for some Class 27 pictures.
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