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In message <Pine.SOL.3.91.990305162231.17581C-100000@leopard>, Peter White <[log in to unmask]> writes > Having done so, I presume that the location with the >sharp curve to which he refers is that near the Lloyd Park stop >on the New Addington branch, where the new line joins the old Woodside >railway alignment, next to which some new housing has been built. Exactly so. > >The 'continuous gradient' (1 in 12) is found some distance east of the >curve, with a section of approximately 400-500 metres of level track >before the curve is reached. Not so. In fact, the part you referred to is extremely steep for a rail line. Most of the part I described, all the way to the bend in question, is actually a downgrade, although obviously not so steep. Trains (and trams) run a very long way on inertia (but then, you known that) > Regarding braking systems, the cars have >rheostatic braking as well as regenerative (i.e. power can be absorbed on >the car itself) Wrong! As I understand the system, the energy is absorbed by the fixed power system, including cooling stations trackside where necessary. Regen braking is often quoted as a sustainable mechanism (re-using the recycled energy. In this case not. And anyway, in a general vehicle control system failure or driver collapse, this would not apply. >, together with spring-loaded disc brakes. In addition, >the fourth braking system (electromagnetic track brakes) is fed from the >electric motors and not the overhead, thus being effective down to very >low speed. The emergency deceleration rate is 3 metres/s/s. Under these >conditions, I see little reason for concern. Yes, but you neither live in the nearby house nor have to ride the trams! > >The Railway Inspectorate of HSE apply very strict standards to all new >light rail schemes, and it would be very surprising if they were to approve >an installation which was unsafe. A useful description of their role may >be found in recent articles in 'Tramways & Urban Transit' by Major 'Kit' >Holden. I hope they do. In this case, all that is needed is a VERY solid concrete catch fence around the outside of the bend, to protect both residents and passengers. The only problem is that the system opens in November! > >Given the relative safety record of rail and road systems, surely the >latter should be Mr Brooks' main concern? >From another message received recently (I was unaware of this incident before).... In Gothenburg there was an very bad accident about 5-6 years ago where a tram set was runing backwords down hill.The trams derailed in the smalest curve on the system (radius about 17 meters). The tram ended in a house and damage som windows. The worst thing was that about 10 persons waiting at a tram stop was killed by the tram. This tram set was runing downhill for about 1 km (gradient about 6-8% all the way) and had a maximum speed of about 60-70 km/h when derailing. In this case the breakes was manually released (the driver can't do this, only servce staff) against all roles! > All views expressed in this >note are my personal views only. > >Peter White >Professor of Public Transport Systems >University of Westminster. > > > -- John Brooks - Consultant in Data Communications, Networking and Energy Systems South Croydon, 7,CR2 7HN, UK Tel: (44) 181 681 1595 Fax: (44) 181 649 7536 The opinions expressed here are mine but are not offered as professional advice. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%