From Richard Holroyd
Martin Savage, in his Pythonesque theorising on the difference in train speeds in summer and winter (21 May, p 25), forgets that not only will the metal rails be longer in summer, but the metal wheels of the engine also get bigger to compensate. Therefore, provided the wheels are rotating at the same speed in summer as in winter, there will be no difference in journey time.
• The editor writes:
…and this is the last stop for this surreal journey.
Cambridge, UK
