Complex sentence: While Rogers was occupied at the ground frame, Newtown signalled that the express was entering the Newtown-Abermule section, but nobody was present in the Abermule station buildings to note the signal.
Split into simpler sentences: While Rogers was occupied at the ground frame, Newtown signalled that the express was entering the Newtown-Abermule section. However, there was no-one in the Abermule station buildings to note the signal.