After building 'specials' and rebuilding existing locomotives, THR started building their own locomotives. When
Rolls-Royce closed its locomotive business, THR took their place in the market place with similar but improved locomotives.
Sentinel Rebuilds Thomas Hill rebuilt various 4w Sentinel vertical boilered steam locos into diesel locos. They removed the steam equipment and superstructure, added new
buffer beams, shunters recesses steps and side skirts. Above the running plates, new superstructures housed either a 6-cylinder Rolls-Royce engine,
torque converter and gearbox (100 hp Sentinel steam locos, classed at TH as "1SDC" – steam-to-diesel conversion) or the 8-cylinder Rolls – (200 hp Sentinel steamer, classed as 2"SDC"). One of these engines, 103c "Megan" and another quite similar (111c) can be found at the
Foxfield Railway These locos were allocated works numbers with a 'c' suffix ('c' for conversion).
Fowler Rebuilds Thomas Hill rebuilt nearly a dozen Fowler 0-4-0 diesel mechanical locos as 0-4-0DH, retaining the frame, running gear and some of the bodywork, fitting new engine and transmission and engine cover. These locos also were allocated works numbers with a 'c' suffix. A batch of 5 were ordered by the MoD – but trials with the first two failed to meet their specified tractive efforts (the original locos were plain bearings whereas TH had calculated assuming roller bearings) and although accepting that they were far superior to the Fowler original, the MoD cancelled the balance of the order.
Vanguards THR was building around 15 new 0-6-0 "Vanguard" locos per year. This arrangement had been agreed by Rolls-Royce in respect of the 0-4-0s but THR were selling 0-4-0s in tandem and even "tridem" which RR considered was to the detriment of Sentinel 0-6-0 and 0-8-0 sales. In addition a number of 0-6-0 specials had also been built by THR. In 1975, the most interesting prospect for new locomotives was the
Ministry of Defence (MOD). For several years they had talked about a replacement programme for their "M" type locos, now it really was going to happen. This was prestige business and competition would be strong. A considerable effort had been made during the previous two years to convince the MOD of the advantages of the Vanguard design well in advance of their enquiry in the hopes of influencing their specification. The strategy paid off and the company was awarded the contract for six locomotives in 1976. These machines proved very suited to the Ministry requirements and three such contracts have now been completed making 18 identical locomotives now in Service. In May 1978, H.M. the Queen, during a visit to Bicester Army Depot, formally named a Vanguard locomotive "Conductor". THR executives were invited to attend the ceremony.
Titan A notable project of the early 1970s was the Vanguard Titan locomotive built for BSC Middlesbrough. The Titan was a rigid frame 0-6-0 loco of 75 (nominal) tons weight. The prototype delivered in August 1972 had two C6T engines with a total rating of 556 BHP. Three subsequent locos which followed at the end of the year were fitted with two C8T engines, total rating 700 BHP. Initially these locomotives proved very satisfactory employed on the heavy ore trains, and five more locos were ordered. Problems began in 1974 with a number of failures resulting in all Titan locos being out of service producing a lack of confidence by BSC which threatened cancellation of the outstanding order. The ability of the locomotives to perform their duties very satisfactorily, and the determined efforts to overcome the problems made by the Company, restored confidence and the order stood. Five Titan locos were delivered to BSC Middlesbrough in 1975. When Middlesbrough replaced the locos with 75ton GECs, the Titans were transferred to BSC Ravenscraig.
Underground Personnel Carriers In 1976 a Heads of Agreement was signed with the
National Coal Board to design and develop a narrow gauge battery electric underground personnel carrier. The vehicle was to seat 4/6 people and was intended primarily for the colliery manager or other officials to use on their daily inspection visits underground. Control had to be simple so that little tuition was required and the vehicle could be safely driven by virtually anyone. Such a vehicle to carry six people was designed and built and, after some considerable delay in approvals by mines inspectorate etc., the prototype termed UPC (Underground Personnel Carrier) was put into service at Bates Colliery in 1977. From the point of view of the initial requirement it was a complete success, but areas for improvement were recognised and incorporated in the 10 production models planned. Unfortunately the vehicle was still classed as non essential to production and was dubbed as the managers Rolls-Royce by men at the pit. It was not until December 1979 that the first actual production UPC was sold, ex stock, to Thoresby Colliery in the North Notts Area The second UPC was used to a greater extent as a general-purpose vehicle which quickly set the pace for further development and little more than two years later, a 24-seater version based on two of the original units with one cab removed and an 18-seat gondola between them, was delivered to Thoresby Colliery. This unit train as it was called, operated well, but again the NCB came up with a number of minor changes and additions which they would like to have made on any future models, which would have had a longer gondola to seat 24. Unfortunately the Miners Strike early in 1984 interrupted plans for further development of this vehicle and no more progress was made.
Valiants Valiants were "remanufactures" using 0-6-0DH Sentinel locos as a base, with some of the superstructure but with strengthened frames, new cabs and control systems. The first two, for Blue Circle Hope, were under-specified and revealed the shortcomings of their Rolls-Royce C8TFL engine, and although spending some months in traffic in 1987-8, resulted in a dispute between BCI and TH and ultimately their replacement with the unique 80ton B-B "Blue John" from
Hunslet-Barclay. Further Valiants were built, but all received the Cummins 14-litre (NTA855) engine, which was proving much superior in the MoD Steelman locos.
Steelman The Steelman is a six-wheel shaft drive loco of 450 to 750 bhp. The first Steelman (Rolls Royce works number 10265) utilised the Rolls-Royce DV8TCA rated at 608 bhp at 1800 rpm and utilised a 2-speed "warm change" Wiseman transfer gearbox, giving the loco a top speed of 40 mph. The follow-on 4 locos – 3 with the Rolls-Royce DV8N (445 bhp) at 52tons and one with the DV8TCE (650 bhp) at 60tons – had re-designed bodywork and single speed transfer gearboxes. All five went to the British Steel Corporation. Rolls expected to develop 2-axle versions to replace the Sentinel models but the sale of Class 14 locos from BR adversely affected the market and without the volume of sales, higher unit costs precluded further development. Following Rolls-Royce's exit from loco building Thomas Hill took over the design, though resistance to it from Thomas Hill (senior) prevented it being offered until long after he'd retired, hence the regressive "Titan" design. The first two TH Steelman locos were built for ICI in 1984, and a sales drive within British Steel Ravenscraig resulted in their taking both the original 60Ton Steelman and the last of the production batch (Rolls Royce works number 10277), which had meantime been the Varlen USA demonstrator and returned. Subsequently, Ravenscraig bought 2 new Steelman 60T 6w's using the Cat 3412, which power unit was also installed into the final 6 wheel Steelman - a 75ton version for ARC Whatley Quarry (Thomas Hill works number 325v). Meantime TH offered a 4 wheel version of the Steelman loco on foreign and domestic enquiries – eventually winning an order for 9 for the MoD in 1986-7. HM the Queen named one of these at MoD Bicester (she had also named an earlier chain-drive Vanguard). Offering a rubber-suspension loco as a "tripper" however was not acceptable to overseas railway authorities, so a coil-spring version was proposed, to be designated a "Steelman Rapide", leaving the rubber-sprung original as the "Steelman Royale". After TH was absorbed by RFS, two "Steelman" locos were produced, but owe little to the original designs, being a 67ton 6w'er for Concoco, and a 150ton 12w'er for Tilcon, Grassington. ==References==