<Tr> <Th> Route length </Th> <Td> 37.5 miles (60.4 km) </Td> </Tr> <P> The Belfast trolleybus system served the city of Belfast, Northern Ireland . It was the only trolleybus system built in Ireland . Opened on 28 March 1938 (1938 - 03 - 28), it gradually replaced the city's tramway network . </P> <P> The Belfast system was the second largest trolleybus system in the United Kingdom, after the London system . It had a total of 17 routes, and a maximum fleet of 245 trolleybuses . It closed on 12 May 1968 (1968 - 05 - 12). </P> <P> In 1936, Belfast Corporation's tramway committee recommended that an experimental trolleybus service be inaugurated after inspecting the Birmingham, Bournemouth, London, Nottingham, Portsmouth and Wolverhampton systems . Seven pairs of chassis from AEC, Crossley, Daimler, Guy, Karrier, Leyland and Sunbeam were acquired . These were fitted with six types of electric motor with coachwork by five different builders, and were supplied on the proviso that should the trial be a success, Belfast Corporation would purchase them and should it fail, they would be returned . </P>

When did trolley buses stop running in belfast