Turning to Barker for some behind the scenes stories.

The entire route for the procession had been surveyed using a landau to represent the width of the State Coach. The author states:
“ A surprising number of traffic islands had moved into the centre of the roads since 1937 which would have divided the procession and brought the huge coach to a stop. These islands were noted and they were all temporarily removed on the evening of 1 June. ”

Perhaps that is why we do not see the State Coach any more these days.

“ Its great weight has always restricted the progress of the coronation procession to three miles an hour, since even the eight Windsor greys can only safely draw its 4½ tons at a walking pace The rear pair of horses are trained to hold back its weight while the other six do the pulling. “