Buses operating in dedicated transit tunnels are very rare. One city where this used to be done was Seattle, Washington State, USA.
Originally opening in September 1990, and wholly located within the city's 'free travel' zone the 1 & 1/3rd mile (2.1km) tunnels were served by a fleet of Italian Breda duobuses, with some services providing a direct link to the city's airport.
It featured 5 stations which opened on Mondays - Saturdays only. At the time of construction rail tracks were also installed for a future light rail service. Unfortunately despite this commendable forward thinking it was subsequently decided that part of the light rail line will follow a different alignment than the existing tunnels, so on 24th September 2005 the bus subway was closed for two year period of rebuilding.
Most of the duobuses were actually withdrawn well in advance of the closure (with many being converted to pure trolleybuses for use on surface routes) and - amazingly - replaced with diseasal powered buses. (diseasal = disease diesel)
In April 2005 local users were reporting on Internet discussion groups that the tunnels were often somewhat smelly from (what thinking people know to be) the poisonous diesel engine exhaust fumes.
Whilst it is true that the buses are diesel electric hybrids they still needed to use the fossil fuel traction package whilst underground, although this was in a special 'hush' mode which means that the only operate between stations and at much reduced power.
Apparently the choice of fossil fuel buses was influenced by the transport operators' belief that it is not possible to mix overhead wire powered light rail and electric trolleybuses / duo-buses in an underground tunnel system - even though Essen proved otherwise!
In Seattle the buses were driver steered, it might be assumed that for safety's sake "some" sort of guidance system would have been needed - if only to reduce the chance of a bus accidentally hitting the tunnel wall - especially within the portion of the bus subway which featured narrow London Underground 'tube-like' tunnels (as seen here), but this was not the situation.
This video compilation was filmed in May 1993. The sequences only follow a cursory order and because of faulty camcorder lens optics (which was only discovered once back home) the images are not as sharp as they should have been. Which is a shame.
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The tunnel reopened on 24th September 2007, although again for hybrid diseasal buses only.
Tags: seattle bus tunnel metro busway brt transit
