CROST: on the track of affordable tramways

Talk by Lewis Lesley

UCL 4th March 2009

Reducing costs

Infrastructure

Not relocating utility plant would not only save considerable disruption (3.4km of utility relocation in Central Manchester in 1991 took over a year), but also costs (utility diversion for the Leeds Supertramway would have been £100m out of a total of £400m). The cost, time and disruption of diverting utilities in Central London would be very high.

The low impact street tramway system proposed for CROST does not disturb under street utilities and maintains access to them, as the foundation trough is only 180mm deep and 380mm wide. It has been in maintenance free operation on the Sheffield Supertramway since March 1996, where it replaced the original track that had failed after just one year.

Electric trams need a power supply. Traditionally this has been via an overhead line, supported from lamp posts, traction poles, or directly from adjacent buildings, without poles. In the UK another source of complaint is that OHL has got heavier and uglier. This commentator likens the Tramlink OHL, to the West Coast Main Line plonked down in the streets of Croydon. There are elegant solutions to OHL. Indeed the tram OHL through the Vienna World Heritage Site, is supported directly off the Opera House, without a mast in sight. Not only are such designs less intrusive than say the Regent Street decorations but they also are very economical and quick to install. This still leaves the need for substations, needed every 2km or so. These have reduced in size and can now be incorporated in existing substations, or included in the basement of an adjoining building.

Tramcars

Trams are not proprietary products and there are many manufacturers who can supply suitable trams to carry the expected patronage safely and comfortably. As the NAO Report noted the main tramcar builders have costs that are much higher than other public transport vehicles, like buses. Many trams are effectively reduced versions of main line trains, and on a per passenger basis, are heavy.

Table 6 Comparison of vehicle weight per passenger

Type of Vehicle	Unladen kg	No. of passengers	Kg per passenger
Bus
Single deck rigid	9000	53	170
Double deck	12000	84	143
Articulated	18000	140	129
Trolleybus	13000	100	130
Train
Metro car (electric)	32500	150	216
Suburban (diesel)	35400	120	296
Tram
Tatra T5C5	19500	100	195
Manchester Metrolink	46000	200	230
Sheffield Supertram	54000	220	245
City Class	22000	200	110

After Lesley 1994

More weight means higher power consumption. The table below shows the comparative power consumption of some different trams in the UK

Table 7 Power consumption of different UK tramcars

Tram type	Weight (tonnes)	Power use (kWh/km)
Blackpool Centenary	18	1.5
Manchester Metrolink	46	4.1
Croydon Tramlink	38	3.9
Sheffield Supertram	54	4.5
City Class	22	1.0

from University of Manchester Dept. Electrical Engineering).

The City Class tram has been extensively tested in Birkenhead and Blackpool.