2 Feb 2010
Theory and practice are two different things - part 2
What was the early experience with diesels? It was claimed that they could keep running 22 hours a day, and the better designs probably could. The difficulty was, and is, that there is not the traffic to keep them occupied in this way, and once complete fleets had been acquired, expensive capital was inevitably kept idle for long periods. This is the economic reality of running a railway. Demand varies over the course of a day, a week, a year, and over the longer economic cycle. Railway equipment can spend long periods out of use over the course of its life of thirty or forty years.
This is why yield management needs to be applied to both short-term and long-term cycles. One solution is to keep a mix of new and old, using the efficient new stock all the time and bringing out the less efficient old fleet to cope with peak demands.