The Friends of the
National Railway Museum

South of England Group
Vice Presidents: Richard Hardy; Sir William McAlpine Bt, FRSE, FCIT, FRSA

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Talk Synopsis

3 January 2006

Clan Line - A New Era Begins
Douglas Padgham
13 November 1995

What was advertised as a talk on the new era beginning for "Clan line", turned out to be two lectures on very different, but equally important, aspects of running a preserved steam locomotive. Firstly, we were given an insight into the research needed to explore the market for large steam motive power. As railway enthusiasts we tend to forget that the enthusiast market cannot sustain the variety of rail tours which are on offer. This was a similar message to that given by Andrew Scott was at our last lecture: "the NRM at York has to remember that the enthusiast is only a small proportion of its market". One of the conclusions of the MNLPS was that in order to market "Clan Line", the locomotive had to be able to handle modern coaching stock - and that meant air braking.

The other lecture was on the installation of the air brakes. The original idea of George Westinghouse seemed to be simple, but the auxiliary items result in a very complex system, especially when it has to work with vacuum brakes. The actual design was based upon that installed in BR diesel locomotives. It was revealing that the cost of the actual compressor was but 5% of the total cost. Indeed, the complexity was such that it took some time to detect a design error whereby the various safety features prevented the system starting up - vacuum could not be created until there was air pressure, but the air system did not work unless there was vacuum! Another area which had absorbed much effort was the exhaust for the air pump. This was not a concern for the operators, but the MNLPS realised that enthusiasts would be offended by steam coming out of the tender. Eventually a solution was found which minimised the offending steam, without the problems found when the exhaust was directed under the tender.

The MNPLS did not regret having chosen to install the air pump in the tender. The result was tucked neatly out of the way , but was accessible for servicing. To have attempted to fit the pump between the locomotive frames would have been much more difficult to accomplish and maintain.

The 2 lecturers were supported by 2 other members of the MNLPS and the evening finished off with a free ranging discussion on a number of technical topics - like the fitting of "Buck-eye" couplings to match Southern EMUs.

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