As in Camberwick Green and Trumpton, the action centres around a small community, in this case the fictitious town of Chigley, near Camberwick Green in Trumptonshire. Chigley is more of an industrial area, and according to Gordon Murray, the three communities are at the corners of an equilateral triangle.
As with the other two series, the original masters seem to have been lost, and the surviving versions of most episodes are extremely grainy and scratched.
Unlike Trumpton, Chigley includes many guest appearances by characters from the previous two series, including Windy Miller of Camberwick Green, and the Trumpton Fire Brigade, complete with their famous roll-call. This was at least partly for economic reasons, as it allowed the established characters' theme songs to be re-used, thus saving money on recording.
Notable new characters include Mr Swallow of Treddle's Wharf, Mr Cresswell, owner of Cresswell's Chigley Biscuit factory, Harry Farthing the potter and his daughter Winnie, and last but not least Lord Belborough of Winkstead Hall and his butler Brackett, who also operate a private railway that seems to run through most of Trumptonshire. Each week Lord Belborough and Brackett can usually be seen rushing to someone's assistance in their vintage steam engine, Bessie, singing: "Time flies by when I'm the driver of a train, and I ride on the footplate, there and back again, under bridges, over bridges to our destination...".
As with the other series, everybody's problems are sorted out by the end of each episode and Lord Belborough invites everyone to the gardens of Winkstead Hall after the 6 o'clock whistle which sounds the end of the day's work at the local biscuit factory. Lord Belborough plays his vintage Dutch organ while the locals dance, and then the episode fades out.