On 12 May, 23:15, Bruce wrote:
On Wed, 12 May 2010 22:31:37 +0100, "Richard J."

wrote:

When you've finished whinging about the whingers on uk.railway (which is
not a group I subscribe to), perhaps someone could answer my question.

Apology accepted.

Most likely because running round would take too long so it needs to
be top n tailed by something. Class 20s rarely run solo as they are
quite low powered I believe.