The infrastructure costs cover many other items
in addition to tracklaying costs:
Signals
Power supply
Depot
Stops
Passenger information systems
Bridges and other road works
Trams are usually driven 'line of sight' on roads; their speed is limited so that they can stop in the distance the driver can see, exactly as recommended for other road vehicles. Signals in the railway sense are therefore unnecessary.
Where other road traffic is already controlled
by signals, there would be additional signals for the trams. The
appearance of these is now standardised across Europe and they
cannot be mistaken by motorists for road traffic signals. More on signals
By having separate signals, the trams can be given priority at
junctions if required.
Example of junction priority
Another situation where signals are necessary is where the tramway is single track and the driver is unable to see the whole section ahead to the next passing place. A simple locally-controlled signalling system would ensure that a driver is warned to wait at the passing place (which is usually a stop) if another tram has already entered the single-track section from the opposite direction.
Many modern tramway systems which work under heavy loading and considerable time-pressure use an elaborate system of signalling and communication with the drivers throughout the system. This is desirable from many points of view but the benefits would have to be weighed against the extra cost.
The overhead power supply equipment for trams usually costs from £80k to £100k per kilometre. The larger expense is in the system of distribution and sub-stations which are necessary to get the power to the wires. An overall cost for the power supply and signalling on a modern tramway of this size (40 km) would reasonably be expected to be £15million.
The cost of the depôt will depend strongly on the type of vehicle in use. For a given passenger-carrying ability, double-decked vehicles will take up much less depôt space than single-decked ones. The height of the buildings will be nearly the same because of the need to accommodate the same height electrical contact wires.
With tramcars which have only one entrance per side, the construction of a tram stop can be extremely simple and cheap. A section of pavement about 4 metres (12 feet) long, raised to about 30cm (1 foot) above road level, is all that is required to give level access to a low-floor tram of the type proposed.
More elaborate shelters and facilities can be provided but these are civic amenities which should receive some financial support from local authorities or other sources of funding.
Details of tram stop arrangements?
The provision of elaborate passenger information systems would be very desirable in the case of an infrequent bus-operated system but, with a frequent and reliable tram system their provision would be mainly cosmetic. A simple indicator such as a route map with small lamps to indicate the position of the trams and their direction of progress could be added to any modern data and signalling system at relatively low cost, if required.
Experience in Croydon and elsewhere shows that correct passenger information is very much appreciated but an elaborate system which fails to give the wanted information can add to passenger frustration.