The broad gauge of the Great Western is associated with one man, namely Brunel.
Fortunately, Brunel rapidly delegated locomotive affairs to Daniel Gooch.
Initial progress was both literally and figuratively rapid
and the broad gauge operated some remarkably fast train services,
but then the standard gauge caught up, and eventually overtook the broad gauge
and locomotive development shifted elsewhere including to Wolverhampton on the GWR
(where the Armstrongs and Dean rekindled locomotive development)
and then gradually returned to Swindon as action shifted towards conversion.
One of the problems with the broad gauge was that the vertical loading gauge
was only slightly greater than that on standard gauge lines.
This probably indicates that Brunel was not fully aware
of the mechanical potential for a broader gauge.