As diesel units were being introduced throughout the country there was pressure on the LMR to build units for the St Pancras to Bedford services. On the 19th November 1956 Mr David Blee, General Manager of the LMR received a deputation which represented most of the authorities whose areas were served by these services. They were also accompanied by Dr C. Hill, Postmaster-General, Mr Christopher Soames, MP for Bedford and Parliamentary Under-Secretary, Air Ministry, and Mr Norman Cole, MP for South Bedfordshire. Mr Blee explained that the problem of the most suitable type of traction unit was being actively studied. "This study, together with the demand for diesel traction units in all parts of the country and the limitations imposed by the production capacity of railway and independent manufacturers workshops, means that diesel trains cannot be introduced in the immediate future on the St Pancras - Bedford line." He also stated that plans were being prepared to convert the goods lines between Harpenden and Bedford so that they could be used for passenger services, enabling improvements to be made in the suburban services. A small working party was to be set up, composed of representatives from British Railways and the local authorities, to confer regularly "with the object of meeting as far as was practical requests which might be put forward by the users of the service."

A study of developments in the population of the outer areas served by the route, and of peoples traveling habits was carried out before the new stock was designed and before the accelerated timings were decided. Construction finally began in the summer of 1958.

At a press conference in September 1958 Mr Blee stated that the first of the units was expected in April 1959, with deliveries expected to be completed by the end of that year, when a new regular interval suburban service from St Pancras was expected to start. This was planned to give a general cut of 10% in journey times between London and the stations covered. Outside the peak hours the pattern of services was to be: an hourly service between Bedford and St Pancras, calling at all stations between Bedford and Elstree; and hourly train between Luton and St Pancras calling at all stations, giving a half hourly service between Luton, Elstree and St Pancras; and an hourly train between Kentish Town and Barking. With augmentation during peak periods there would be 18 more trains each week day, and during peak periods 8-car trains were expected to be run. There was to be roughly 30min cuts to the journey time between St Pancras and Bedford, and about 20-25mins to Luton. The diesels would not provide a service to Moorgate, although these services would be speeded up. At a cost of £2.5 million, the scheme was the largest of its kind so far, but this cost included £400,000 for the provision of a maintenance depot at Cricklewood and the long awaited upgrading of the goods lines to passenger standards, together with improved signaling arrangements.

He stated that saloons were to be fluorescently lit, using the then new transistor equipment. Each 4-car set would have four 238hp Rolls Royce engines with hydraulic twin-disc torque converter, which had just been exhaustively tested on E50000 with very promising results. Mr Blee also announced that this scheme would be followed by a similar one, covering the Marylebone suburban services, requiring 15 4-car sets, and gave further details on the Blue Pullman project, for which the Midland sets were also expected to be based at Cricklewood. It was also thought possible that two diesel parcels vans would be included in the rolling stock for the St Pancras scheme.

More detailed plans from September 1959 showed that Bedford would have 44 instead of 31 trains other main-line expresses to and from St Pancras, Luton 88 instead of 50, St Albans 100 instead of 79, and Elstree 45 instead of 30. By semi-fast diesel train the running time for the 49 miles from St Pancras to Bedford would be 70 min, to Luton (31 miles) 43 min, St Albans 28 min, Elstree 20min. Trains stopping at all stations would take a little longer. DMU stabling sidings were installed at the north end of Bedford station.

Delivery

The first set ran into St. Pancras on the 14th May 1959, for crew training purposes. As further units were delivered, the training was stepped up, and a problem emerged. Test runs to Moorgate had to be abandoned as their body lengths caused clearance problems in the tunnels.

Crewe training continued until the 28th September 1959 when they were introduced on preliminary services. There worked eight off-peak services a day, to the existing steam timings as all the parts of the project were not complete.

Poster advertising the start of provisional services. "Monday, 28th September, will see the introduction of some of the new multiple unit diesel trains. Until all the new trains have been received from the London Midland Works at Derby and the maintenance facilities at Cricklewood are in operation a mixed service of diesel and steam trains will be run. To begin with, the diesel trains will run during off-peak periods. To allow for interchangeability, the times of all trains have had to be planned on the basis of steam train times and will be similar to those which applied last winter. The full diesel service with more and faster trains will start on Monday, 4th January, 1960. It is hoped that you will like the comfort and appearance of the new units."

The Mayor of Bedford, Alderman C. N. Barrott, welcomed a party of guests during the first day at a ceremony at Bedford Midland Road. He expressed the satisfaction of his community that it's interests had been considered in effecting improvements to the service. The new trains would provide facilities better than those for which Bedford had hoped, and he was pleased that many others at intermediate stations would benefit.

In reply the LMR General Manager David Blee stated that the new service was an example of how sensitive railway management was to the needs of the traveling public, although he said that the biggest difficulty in facing the demands of this kind was the time factor in producing the new rolling stock and in improving track, signaling, and intermediate stations. The people of Bedford and neighboring communities had asked for the new service. It had cost £2,500,000. He said that if their request was genuine they should now patronise it to enable British Railways to obtain a good return, and that he hoped the results would increase prosperity in the area.

Mr Blee speaking at Bedford after the arrival of the inaugural diesel train on September 28th.

Attendees at the ceremony included JF Harrison, CME of the BTC Central Staff, from the LMR: EW Arkle, Director of Traffic Services; AE Robson, CMEE; RW Crawshaw, Public Relations & Publicity Officer; RLE Lawrence, Divisional Traffic Manager, London; WN Roberts, District Passenger Manager, Euston; JC Rogers, District Operating Superintendent, St Pancras; and CJ North, District Motive Power Superintendent, Kentish Town. There was also Mr Alan Lennox-Boyd, MP for Mid-Bedfordshire; Mr Christopher Soames, MP for Bedford; and the Mayor and other representatives of communities served by the new trains.

Full Implementation

This was put back a week to Monday 11th Jan, because of a delay in completing engineering works, caused by a shortage of skilled building labour in the London area. The LMR made a vigorous effort to win traffic, with the combination of the comfortable new trains, the faster and more frequent services, and the introduction of a special cheap day return ticket to encourage off-peak travel. Parking facilities were improved at outlying stations to encourage people to 'park and ride'.

The general principle of the new timetable was one train leaving St Pancras at every hour for all stations to Luton, and one at 35 min past every hour for Elstree and all stations onwards to Bedford. With the eight intermediate stops the time to Bedford was no more than 69 mins for the 49.8 miles. In the opposite direction, the semi-fasts from Bedford and the stopping trains from Luton all left on the hour, resulting in a half-hourly service to and from Leagrave, Harlington and Flitwick.

The superior acceleration of the diesels made it possible to cut the headway over the bottleneck between Kentish Town and Finchley Road, allowing inconvenient gaps in the rush hours to be closed. There had been no train from St Pancras to Luton between 17:58 and 18:50, there was now a 17:55, 18:15, 18:48 and a 19:00. Bedford got a 08:30 to break the interval between the 07:55 (retimed to 08:05) and 08:53 departures. On Monday to Fridays, the last Bedford train left at 22:35 instead of 22:00 and was 20 minutes faster, and the last Luton left at 23:35 instead of 23:15.

The speeding up of the services saw some of the timings as fast as 21 mins for the 19.9 miles from St Albans to St Pancras, and 26 mins for the 24.6 miles from Harpenden. In the opposite direction the fastest services were 23 and 28 mins respectively. Some of the timings were faster than those to and from any other London Terminus over a corresponding distance. The improved signaling over the upgraded former goods lines, and the new platforms at Luton, Leagrave, Harlington ad Flitwick made it possible to keep most of the stopping trains clear of the fast main lines, meaning minimal interference with the long-distance expresses.

Services between Kentish Town and Barking were also taken over by DMUs on that day with an improved timetable, although this was critisised as most Kentish Town connections just missed the St Pancras - Luton stopping trains.

Initial Problems

Of the 30 sets built, 26 were required for peak periods, leaving only 4 spare for maintenance or other service requirements. But the sets, with the then new and non-standard transmission, were beset by various teething problems. In the peak hour periods, failures occurred at places and times which caused havoc to other services. Operating difficulties arose through having to adjust set workings, with trains running out of course. Trains had to be cancelled and additional stops inserted, and trains stopped short of their destinations to get a quick turnaround. Additional units had to be brought in, and some services returned to steam.

The problems were given prominence in the newspapers (such as The Daily Telegraph of 23/1/60) and aroused much criticism from the impatient traveling public. David Blee and his principal officers got involved, reviewing the cause of the trouble, the steps being taken to put it right, and a likely date when services would be back to normal. He said in a statement that none of the troubles experienced had shown up in the extensive trials the sets operated before the full introduction, which if they had would have been dealt with without materially affecting the service. He said the types of trouble could not have been foreseen, and the reserve of four sets has proven insufficient . A regular traveler replied to this, stating that he had " observed many disappointing features both in operating and in public relations, in most cases suggesting near-panic." Both railway and contractors staff worked day and night and weekends to correct faults and remove causes and senior officers kept a close daily check on train operations. 

By the beginning of April 1960 the Region stated that most of the difficulties had been overcome. Passenger figures were also released for the month of February, the first full month of operation. The number of journeys by non-season ticket passengers rose by 19.5% compared with Feb. '59, from 261,180 to 312,221. Receipts increased by 24.3%.

In April '60 a meeting was held, attended by Mr RLE Lawrence, Divisional Traffic Manager, London, LMR, and the Joint Committee of Local Authorities, to review the new services. The spokesman for the JC congratulated the railway management on the success of the scheme. The LMR stated it would increase the number of vehicles in service if this was found necessary and would remove the armrests between the seats to increase seating room. 

The LMR announced at the end of July '60 a passenger increase of nearly 20% on the line after a review of six-months operation.

Operations

It was claimed that the St Pancras - Bedford service was the most intensified DMU service in Europe. The 26 diagrams daily gave a total mileage of 5,205, corresponding to @52,000 miles per annum per set, and each set covered approximately 1.5 million miles in their lifetimes. Daily diagrams varied between 85 and 450 miles. The sets were built only for this one route, and rarely ventured from it, earning them the nickname of "Bed-Pan" units.

There was the occasional strayings. For several years in the mid '60s the 14:35 St Pancras to Bedford was extended to Gretton, which was between Corby and Manton, returning at 16:40. In the late '70s they worked a service from Kettering. The vehicles traveled out light to form the 05:45 to St Pancras. An eight car set which worked a Bedford to Southend excursion on the 28th July 1973. The Pope's visit, and the ASLEF dispute in 1982, saw workings as far as Leicester.

Faults

The most serious problem between 1960 and 1966 was fires, mainly caused by defective exhausts, or cardan shafts breaking and puncturing fuel tanks. This resulted in the No. 2 engine exhaust pipe being re-routed, and the thickness of the cardan shaft wall increased. The fuel tank shapes were also redesigned, and the tank walls thickened. To aid evacuation, steps were added to the DMBS to help passengers climb down to the track safely, and an access door was formed in the wall dividing the two saloons.

The heavier Self Changing Gears Ltd. final drive had been used on other 238hp engined sets and showed promising results when used with mechanical transmission. However, when used with the torque converters on Class 127s they developed a number of weaknesses. These were mainly due to fractures of the striking fork, as happened on the lighter drives for 150hp engines, and failure of a lip of the parallel roller bearings which support and locate the secondary bevel gears. These bearings were strengthened and more positively located. The defects were normally detected during special depot examinations so few failures occurred due to this in service.

Performance

On an inaugural run for a press party from St Pancras to Bedford, with an 8-car set, these timings were taken. Kentish Town was passed at 51mph, and up the 1 in 182 through Belsize tunnel speed increased to 57mph. The short descent from Cricklewood produced a maximum of 70mph. The press, as they could now see the same view as the driver, quoted surprise at seeing that there was a 60mph speed restriction through Hendon as steam drivers showed scant regard for it. However, the driver on this press trip carefully eased the units down to 58mph through the station, which 6.9 miles from the start was passed in 8mins 17sec.

The most impressive demonstration give to the party followed, as for the 5 mile climb to Elstree, mostly at 1 in 160-176 the speed rose steadily from 58mph to 70 mph and Elstree, 12.4 miles, was cleared in 13mins 20secs. The driver eased of the throttle, so no higher maximum was reached than 72mph on the descent to Radlett, which was passed in 15 min 41 secs (15.2 miles). 'Even time' from the start was just attained at milepost 19, passed in 18mins 53secs, and with a slow stop St Albans, 19.9 miles was reached in 20 mins 23secs.

The 4.7 miles from St Albans to Harpenden, with the first mile from the start at 1 in 176 up, was run in 6mins 34 secs start to stop, the 74mph at which the Chiltern Green was passed was the highest of the journey, though in general the 70mph nominal limit for these units was closely observed. Thus down the long 1 in 200 descent from milepost 34, after leaving Luton, speed was restrained for almost the whole distance to a maximum of 71.5mph. Leasgrave, 2.6miles, was passed in 3mins 43secs; Flitwick, 10.0 miles in 10mins 4secs; and milepost 16 in 15mins exact; the rest of the run was spoilt by a long slack for drainage.

The same slack hampered the start of the up journey, but from Houghton Conquest the speed recovered up 1 in 200 from 20 to 66mph at Amphill. The controller was then moved back a notch, so that speed in the slight dip after Flitwick did not exceed 71.5 mph, and 70-69 was then maintained up the whole of the 1 in 200 to milepost 34. Because of the permanent way slowing, it took 11 min 5 sec to pass Amphill from Bedford (8 miles); the 12.5 miles to Harlington took 15mins 1 sec, the 17 miles to Leagrave 18min 57sec and the 22.5 miles to Chiltern Green 23 min 57 sec, including a 50 mph signal check at Luton and a re-attained 70mph before Harpenden Junction. From there onwards there were many checks and nothing of note other than a 69 mph up Elstree.