In his book, 'Edinburgh Transport, The
Corporation Years' [ISBN 1 8744222 3 0]
G L Hunter
"In early 1921 there was a prolonged strike in
the mining industry and ... some of Edinburgh's charabancs were
temporarily converted to lorries to assist in moving coal."
The photograph above was taken
during the miners' strike. The strike began on April 1, 1921.
It lasted for about 3 months.