Maximum hill climbing, and braking down hill is not dependent on vehicle weight but the number of driven axles and the control system used. The steepest tramway with only wheel/rail adhesion was in Montreal (14%), which the replacement buses could not manage in winter. As a number of you have pointed out Lisbon has 12% gradients with all axle powered trams, coping with in all weathers for over 100 years. Trams used to climb the steep hills of Bath until 1939. The steepest gradient in the UK is Sheffield 10%, with all powered axle trams operating up and down safely since 1995. These are supply side points.
The more important point is how well a new tram system in Bath will attract trips from cars, and so reduce traffic (volumes, congestion and pollution) (Croydon trams reduced car traffic by 20%), and will that be enough to cover both the operating costs, and retire/depreciate the capital investment. This will be the crux of a Feasibility Study. Fortunately travel behaviour of a population is known and can be deduced for trip transfer to tram, for a wide range of competitive choice scenarios, including travel cost, journey time, convenience etc.
Prof. Lewis Lesley BSc, AKC, PhD, CEng, FRSA, MICE, FCIT, MTPS.
rom: info at CJHM [mailto:info@cjhmultisourcing.
Sent: 12 February 2018 21:02
To: dave andrews <firstname.lastname@example.org>; adrian howson trams <email@example.com>
Cc: David Walmsley <firstname.lastname@example.org>
Subject: Re: Gradients
I repeat yet again there are trams available that are rated for 12% in all weathers.
I have personal been on trams in Lisbon starting fully loaded in a rain storm on 1 in 6 hills that buses have problems with.
The correct driving technique coupled with traction control system can overcome any issues.
In some Swiss cities they have trams starting on 1 in 5 inclines in snow storms.
Coupled with the fact that trams used to operate in Bath I can foresee no issues.
Time to put this to bed until there is a full feasibility study…..