The time of the trolleybus
FRANK BEETON looks back in time to the era of the trolleybus …
While I was doing some research for a recent FOCUS article, I got to thinking about the trolleybuses that used to glide silently around major South African cities about half a century ago. What with all the current attention focused on alternative driveline vehicles, we sometimes forget that methods of propulsion other than internal combustion engines have been around since motor vehicles were first invented, albeit in vastly different forms to those existing at present. It is sometimes useful to look back at the technologies of the past to better understand our direction for the future.
In essence, trolleybuses were conventional road vehicles driven by electric traction and drawing their current from an overhead power supply. The principle became popular when cities were looking to improve on trams, which could carry vast numbers of passengers, but needed fixed rail infrastructure to operate. In modern parlance, trolleybuses could be described as “crossovers”, combining the basic technology of a motor vehicle with the electric motive power of a tram. The early manifestations were understandably crude, but by the mid-1930s they had evolved into possibly the most sophisticated form of urban public passenger transport.
The main benefits were smooth, clean and silent running, ease of operation, and better hill-climbing ability than contemporary motorbuses. They were also able to draw into the kerb to collect passengers, whereas tramlines usually ran close to the centre of the road, making boarding and alighting hazardous for tram users, especially when vehicular traffic started to increase.
Technically, early trolleybuses shared chassis and axle components with their fossil-fuelled brethren, but with an electric traction motor taking the place of the engine and gearbox. Their fairly substantial amount of switchgear and control equipment was normally placed in an enclosed cab alongside the driver. Current collection was by means of two roof-mounted poles, or “trolleys”, which engaged with the overhead catenary. In the cab, the accelerator pedal was placed on the left – to remind the driver that he was tied to the wires!
The first trolleybus services in South Africa ran in Boksburg and Germiston during the First World War, but proved to be short-lived. A more permanent operation took root in Bloemfontein in 1915 but, surprisingly, this was phased out in 1937, just when more extensive networks in Cape Town, Durban and Johannesburg were coming into their own. Pretoria was the last city to join the “club”, with its first trolleys entering operation in 1939, just as the Second World War was getting under way.
The early vehicles all came from British manufacturers, including Ransomes, Leyland, AEC and Sunbeam. Post-war, Leyland and AEC combined their trolleybus interests in British United Traction (BUT), but Sunbeam continued to supply all the local networks, and Johannesburg also flirted briefly with Italian manufacturer Alfa Romeo, which contributed some giant 85-seaters to the Highveld scene in 1958.
Trolleybus operation peaked in 1961, with 436 vehicles in service in four South African cities. By then, however, operational concerns were raising their heads. Most related to interaction with other vehicular traffic and the restrictions posed by reliance on the overhead infrastructure. The main problem was that trolleybuses were unable to overtake each other, and their pace was always determined by the slowest at the head of any particular group. There was also the problem of negotiating points, or “frogs” in trolleybus parlance, which required the driver to cross the intersection with power applied to activate the turning switch.
This often caused problems when traffic conditions were not favourable, and buses could sometimes be seen with one trolley still on the “main line”, while the other had taken the “branch line”. Such an arrangement was clearly not sustainable and the bus soon came to a halt with trolleys waving around in mid-air. Most crews were then required to catch the errant trolleys with a hooked bamboo pole, although Pretoria provided a more convenient solution, with permanently attached retriever ropes attached to the trolleys.
City Tramways in Cape Town was the first of the larger operators to abandon the trolleybus, (or “trackless tram” operation, as they called it) in 1964. Durban followed suit in 1968, followed by Pretoria in 1972. Johannesburg persevered for quite a while longer, and even conducted an experiment with new-technology vehicles in the early 1980s. This did not prove successful, however, and the JMT system eventually shut down completely in 1986. Patrons of the various services were not happy with this development and many column centimetres in city newspapers were devoted to heated debate around trolleybus withdrawal.
Ironically, the arrival of the Bus Rapid Transit system, operating on exclusive right-of-way, or on roads where access to other traffic is restricted, has revived global interest in the trolleybus. The modern versions can also have auxiliary diesel engines, which provide some mobility away from the overhead catenary. It is not beyond the realms of possibility, therefore, that trolleybuses could make their reappearance in South Africa sometime in the future.
Until then, however, we can satisfy our curiosity by visiting the James Hall Museum of Transport at Wemmer Pan in Johannesburg, where several pristine examples have been preserved for prosperity. Go and take a look!
Rear-view Focus is a column by FRANK BEETON that takes a nostalgic look at the truck and bus world of yesteryear. Visit www.focusontransport.co.za to comment on the column and share your memories with us.