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SJ Standard Railbusses   By Rory Wilson
A working life of forty years is by no means rare for steam, diesel or electric locomotives, or even for electric-units; but for a lightweight diesel-railbus design to still be in normal service fifty years after design work started is unusual. The half-dozen Y6 railbuses that are still in service on the Lemvigbane and Vestbanen in Denmark, together with the large number of similar vehicles in Benverket, VR and even NSB use, testify to the success of a design that will be familiar to anyone who has travelled in Scandinavia in recent years.


In 1944 SJ, needing to replace its heterogeneous collection of mostly four-wheeled railbuses, set up a working-party to produce guidelines or future construction. The group examined the few modern steel-bodied designs that were in use in Sweden at that time and was particularly impressed by the three railbuses built by NOHAB for the HNJ in 1938. It also used some of the older wooden-bodied railbuses to try out such ides as Scharfenberg couplings, fluorescent lighting and hydraulic gearboxes. The following year, the group produced its report, which recommended steel-bodies and multiple-working for future orders, and design work began.


By spring 1946 three versions of the rough design were ready: one or two-engined standard-gauge or single-engined narrow-gauge. In summer 1946 SJ asked for tenders for sixteen narrow-gauge railbuses and eight trailers with Scania-Vabis diesel engineers and Atlas hydraulic transmissions; delivery was to take place between April and November 1948. ASJ, General Motors, Hilding Carlsson, Hagglunds, Kockums, KVAB and NOHAB were asked to tender; Hilding Carlsson wanted to build his own design - basically a steel version of his wooden-bodied railbuses - whilst General Motors had withdrawn from railbus construction and referred to SJ the newly-formed Marstaverken. In September 1946 Marsta gained the order, but later found itself unable to deliver on time. The first test-runs did not take place until spring 1948 and the first deliveries were not until the following January; only in the spring of 1949 did they begin in earnest. Because Atlas had ceased production of the chosen transmission-unit, the last two of this batch were built with Wilson-Planet transmission, which became standard on all subsequent deliveries. Despite not having taken delivery of a single railbus, SJ ordered a further ten railbuses and seven trailers from Marsta in May 1948; two more railbuses were added to this order in July. As soon as the first railbuses entered service the problems began: overheating engines, axle failures, poor braking performance and problems with the Atlas transmissions. SJ persevered with the vehicles in order to learn as much as possible about the problems and did not take them into works until 1952, when the work carried out included the replacement of the Atlas transmissions in the earlier vehicles by Wilson ones. By mid 1950 SJ had produced its definitive narrow-gauge design (YCo5p) and in July ordered 15 railbuses and 15 trailers from Hagglunds, all for the 891mm lines; no more vehicles were to be built for the 1067mm lines as the writing was already on the wall for this gauge.


SJ's design section has been progressing with the standard-gauge YCo4 (singled engined) and YCo5 (two engined) designs. In spring 1947 tenders for four railbuses of each type and two trailers were requested from the same firms as before (including General Motors), plus Marsta. The vehicles were to be delivered between March and July 1949 and would then be extensively tested before SJ came back in mid 1950 with a large order, which could incorporate any necessary modifications. Kockums won this order, but failed to produce the vehicles on time - partly due to detail alterations to the design by SJ - and in November 1949, four months after the last vehicle should have been delivered, reported that the first railbus would not appear until 1952 - much too late to allow trials to take place. Finally, in November 1950, the order was cancelled, the two-engined deign being abandoned at the same time. It could be pointed out that Martsa was a completely new firm, whilst Kockums' experience of railbus building was limited to a handful of heavyweight vehicles in the 1930s.


Hilding Carlsson had been forced to take notice of SJ's requirements, partly because the disappearance of most of the private companies had left SJ as his only large potential customer, and he had developed a design similar to the SJ one; not surprisingly, as he was aware how much SJ had been influenced by the HNJ vehicles. However, it did include a number of important differences, most notably in having the air-intakes in the vehicle-ends and being designed with Wilson transmission from the start. Holding Carlsson knew that his design had impressed SJ, but despite its advanced state of development and similarities to their own design, SJ felt that it did not fully meet their requirements and persevered with their design, finalising it in min 1950 under the classification YCo6. This differed from the Hilding Carlsson design by being 1 metre longer, 3 tonnes heavier, being fitted with a 200 h.p. (instead of 165 h.p.) engine and in having the engine air-intakes placed under the vehicle, so as to allow communicating-doors in the vehicle-ends. In July 1950 SJ asked for quotes for 40 railbuses and 35 trailers from ASJ, Hilding Carlsson (who replied by offering to build his own design instead), Hagglunds, KVAB, Motala, Marsta and NOHAB; Hagglunds won. Hilding Carlsson, who was unhappy that SJ had refused to accept his design and that the July 1950 order for narrow-gauge vehicles and this order was awarded to Hilding Carlsson in December 1950; this contract was later extended to total 24 railbuses and 28 trailers. The first four railbuses of the standard-gauge design left the Imea works in later 1950 and, together with four trailers, went to the TGOJ (Y Cos 51-54 and UCFos 109-112). Once a few modifications had been made, SJ was prepared to accept the design and acquired four similar bodied vehicles; they were classified YCo4 as no vehicles had been built to the original YCo4 design. The first YCo5p narrow-gauge vehicle was ready in May 1952, but yet again there were problems: heating of the vehicles, engine cooling and a toilet that was too small for the more generously proportioned Swedes. Despite this, SJ placed a large order for narrow-gauge vehicles in June 1952.


In early 1951 tenders were asked for 40 YCo6 and 38 trailers which were urgently required; this order was won by ASJ, which was to build the railbuses at Linkoping and the trailers at Arlov. KVAB's tender has been lower, but as the delivery would have been slower it had to make do with the consolation prize of an order for 20 YCo6 gained in June that year. In June 1952, despite not yet having taken delivery of any YCo6, SJ asked for tenders for a total of 250 railbuses, 30 of which were to be electric with ASEA equipment and 230 trailers, all to be delivered over a period of five years. ASJ won the order for the railbuses, with delivery to follow on as soon as it had completed the previous order in early 1954, whilst Eksjo won the order for the trailers, which were to be delivered from early 1953. The details of each year's order were to be given in advance; in September 1952 the 1954 requirement was set at 50 railbuses, 15 of them electric and 46 trailers.


The first YCo6s arrived from ASJ and Hagglund in early 1953, with KVAB's first example following a few months later. Priority had been give to railbus production and the trailers did not start arriving until the end of the year; elderly four-wheeler trailers being used as a stop-gap. Once again the railbuses suffered from teething problems: bogie fractures, gearbox failures, leakage of hydraulic fluid, damage due to dirt or snow either blocking or finding their way into the under-vehicle air-intakes, poor riding-qualities and fires due to problems with the heating system. In February 1955 a working party was set up to study the problems and its suggestions, which included moving the air-intakes to the vehicle-sides and a new heating system, were applied to new vehicles on building and to the older ones during works-visits. As the problems were solved and staff became more familiar with the vehicles, reliability improved.


The 15 YCoa6 electric-railbuses due in 1954 did not arrive until the following year and also suffered teething problems: excessive wear of the brushes and commutator, high oil temperatures, the cardan axle flying off, excessive noise and vibration, a too small transformer and insufficient ability to haul trailers. By the end of 1955 many were stored and rebuilding, which included a new transformer, started in June the following year. The last 12 of the second batch were classified as YCoa7 as they were built with 2 + 2, rather than 2 + 3 seating.


In June 1954 the 1955 requirements were set at 50 railbuses, including the remaining 15 electric ones and 46 trailers; in February 1955 the 1956 order was also set at 50 plus 46. During 1955 SJ realised that it was going to end up with too high a proportion of trailers and it was agreed that Eksjo would build railbuses to ASJ's drawings; although they were building standard designs, each manufacturer produced its own drawings. In June 1956 the 1957 and 1958 orders were set at 50 YBo6, as they had become following the disappearance of third class on 3 June 1956, from ASJ in both years; six YBo6 and 40 trailers from Eksjo in 1957 and 46 YBo6 from them in 1958. Later it was decided to build YBo7, which differed in having 2 + 2 seating, and all Eksjo's railbuses and the last 80 of the ASJ's were built as such. One extra YBo6 (1260) was built by ASJ at Arlov in 1957 as a replacement for 861, which had been destroyed in an accident at Shimrishamn on 6th March that year. Later SJ was to order 12 trailers from ASJ in November 1957 and a further 50 from Eksjo in February 1959; UBFo7ye 2906 was delivered on 10 January 1961, the last of 916 vehicles built for SJ (excluding the Hilding Carlsson built YCo4 667-670).


SJ had placed an order with Hilding Carlsson for 85 891mm gauge railbuses and 60 trailers in June 1952, with delivery commencing once the previous order has been completed in 1954, with delivery commencing once the previous order has been completed in 1954 and to spread over five years. By 1957 it was realised that closures meant that the full order was no longer required and it was cut back to 52 railbuses and 46 trailers; Hilding Carlsson receiving the order for the X9 e.m.u.s. as compensation. In March 1962 another examination of future narrow-gauge rolling-stock needs resulted in a decision to withdraw all the expensive to maintain Marst-built vehicles, as well as all the non-steel types, as soon as possible; they had all disappeared from the 891mm system by the end of 1967. To eliminate the Marsta vehicles from the Karlshamn-Vislanda line, the last section of 1067mm network with a passenger service, five YBo5P and two trailers were rebuilt at Malmo and Växjö in 1964; they were withdrawn when the line succumbed in 1970. SJ continued to use its dwindling number of narrow-gauge railbuses, all the non-passenger trailers and many passenger ones having been withdrawn by the early 1970s, on the diminishing narrow-gauge network, moving the vehicles in better condition around as lines closed. The closures of 1972 left only the Växjö-Vastervik line and the Roslagsbanan with passenger services: the latter was sold to Stockholms Lokaltrafik in May of that year, together with twelve Yp railbuses as they had been reclassified in 1970, and twelve trailers. The RB had originally planned to use locomotives and railbuses suitable for hauling trailers, rather than the SJ design, but following the takeover by SJ on 1 July 1959, YBo5p were drafted in to work services to the north of Rimbo as well as the FINLANDAREN between Norrtalje and Stockhom O. After the closure of the lines north of Rimbo, the YBo5p took over the Rimbo-Norrtalje line until its closure in September 1969, as well as the through Stockholm-Rimbo trains. From 1972 to 1974 the railbuses worked all services to Rimbo and took over the Djursholms Osby-Eddavagan line from Spring 1973 until its closure at the end of 1975; they were out of use from 1978 (except for a brief return in the summer of 1981), but the last three were not finally withdrawn until 1987. Five of the RB's railbuses found their way back to SJ for the Vaxjo-Vastervik line in the early 1980's, but this line shut in August 1984 and SJ's last narrow-gauge railbuses were withdrawn.


Over the years there have been a number of modifications to the standard design. The first of note was in late 1954 when 1000 and 1001 were fitted with a second toilet, a pantry and aircraft-seats of blue DC-4 type in 1000 and red DC-6 type in 1001; reclassified YCo8, they were used in the 'Harjedalingen' night service from Stockholm to Hede. The service did not last ling and they ended up at Kalmar working on a special diagram to Nassjo until result to YBo7 standard in 1960. In the last 1950s a few trailers were rebuilt with first-class seating and a pantry for use on the Blekinge Kustbana (Malmo-Kristianstad-Karlskrona), a few more were late converted for Goteborg-Kalmar and Stockhom-Mora services, in the latter case without a pantry. In 1959/60 a number of non-driving passenger-trailers were rebuilt as driving-trailers. In late 1963 the classification YBo8 was applied to four YBo6 refurnished with more comfortable seating for use on the lines from Oskarshamn to Linkoping and Nassjo, a further twenty-three railbuses and four trailers were similarly dealt with late the following year, mostly for use in northern Sweden. Many vehicles have been given new interiors and changed classification, most commonly from YBo6 to YBo7 and there were many minor or temporary alterations, including three vehicles refitted as inspection vehicles. During the 1960s a handful of vehicles received a large 'panorama' end-window to eliminate the vertical support between two of the smaller windows that had been directly in front of the driver, a further fifty were dealt with during the 1970s.


From their introduction the railbuses were used on local stopping and semi-fast services on both electrified and non-electrified lines throughout Sweden. Many of the early YCo6 were sent to northern Sweden to replace the older railbuses and steam locos, but in turn they were displaced southwards by the more comfortable YBo7. The closures of the 1960s resulted in many withdrawals; the four Hilding Carlsson YBo4 went in the early 60s, whilst the Hagglund and KVAB series, together with the first batch from ASJ, had all gone by the mid-70s (except for 786, which lasted until 1981). Many non-driving trailers were early victims of the cutter's torch, which most postal-trailers disappeared following a reorganisation by the ppst office in 1968, although a few remained until 1975, mostly for use Malmo-Ystad and Nassjo-Oskarshamn. By the time the Y1 railbuses were ordered in 1977 the run-down had reached such a state that repair had to be carried out on a number of Y7 and Y8 to keep them running and some withdrawn examples had to be reinstated to cover shortages. The Y1s started arriving in 1979 and were initially sent to northern Sweden to displace Y7s and U8s southwards. Continued deliveries of Y1s and further closures reduced the requirement for older vehicles; the last Y6 was withdrawn in 1983, the last Y8 in 1984 and the last four-wheeled trailer in 1985; the last trailer vehicle of all (UBF7Z 2069) was withdrawn in 1987. The last railbuses went in 1989, their last regular working having disappeared when the Sjotofta-Ulricehamn line closed on 12 June 1988, although three has been kept as an emergency reserve at Boras during the winter of 1988/89, although they were not used, and a handful were used on the Mellerud-Bengtsfors summer service in 1989. After spending most of their working life in central and southern Sweden, the electric railbuses were concentrated on Gavle for their last few years before withdrawal in 1987, mainly working on local trains to Ljusdal. As early as 1966 a YB06 was rebuilt as a mobile workshop and over the years over one hundred have gone into engineering department - now Banverket - service as workshops, stores vehicles, personnel-carriers and OHL maintenance vehicles, including two of the latter on the Roslagsbanan (one having replaced the other).


A number of other Swedish railways have owned railbuses of this type; as mentioned above, TGOJ had four examples of the original Hilding Carlsson design and four similar trailers, all were gradually old after being rendered surplus by electrification in 1956. Between 1956 and 1959 Holding Carlsson also sold three four-car and ten two-car e.m.u. sets with bodies based on his diesel designs to TGOJ. In 1985/1986 TGOJ bought four electric railbuses and one trailer from SJ (X16 959/974/975, X17 976 and UBF7Z 2076); all were withdrawn before the end of 1988. The 891mm NKIJ had two three-car e.m.u. sets of Hilding Carlsson design called 'Uddeholmaren' which were only used in passenger service between 1956 and 1964. The GSJ ordered five railbuses and three trailers of YCo6 type from ASJ in mid 1952, they were delivered in 1953/1954 as YCo6 1-5 and UCot 11-13. As a result of the GSJ's closure at the end of 1965 all, except for UBoy 13, were sold to LAMCO (Liberation American Swedish Mining Company) for personnel transport in Liberia; LAMCO also bought TGOJ YBos 54 and SJ YBo6 827/





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