wrote in message
...
On 18 Mar, 13:59, EE507 wrote:
On Mar 18, 1:20 pm, John B wrote:

Indeed, 90s sounds like a fault to me, especially at open-air stations
south of London Bridge where the southern 377s' GPS should already
know where it is (from use on the Brighton - Watford Junction and
Charing Cross - Caterham etc. services)

Would not wheel revolutions help?