Prior to the introduction of the new local Dudley network on Monday 1st October 1934, Birmingham and Midland Motor Omnibus Company Limited (BMMO—Midland “Red” Motor Services) ran Service 140 between Birmingham City Centre, Dudley Town Centre, and Gornal Wood. They also ran Service 141 as a short-working variation over the same route between Dudley and Gornal Wood only. With the introduction of the new network, Service 141 was renumbered to local Dudley Service D40 and Service 140 was shortened to only run between Birmingham and Dudley.
In the early 1930s, departures towards Gronal Wood from Dudley Town Centre on Service 140 and Service 141 had been from Union Street, just off the High Street. By 1940, the departure point had moved to King Street, but unfortunately I've not been able to establish when this change took place so it may have been before or after the introduction of Service D40. Buses ran via Wolverhampton Street and Bagley's Lane with a frequency up to every 10-minutes. Service D6 also ran between Dudley and Gornal Wood but took a more direct route along Himley Road, and buses on the D6 route were less frequent.
in c. 1951, new Service D41 was introduced as an extension to Service D40, running over the same route to Gornal Wood and then continuing to Stickley Estate (Lower Gornal), which in the early 1950s was undergoing expansion with new housing being built. Around the same time, Bagley's Lane was renamed to Dibdale Road but to avoid confusion BMMO would show both names for this road on their timetables for many years to come.
The new “Fisher Street Omnibus Station” was opened near to Dudley Town Centre on Saturday 27th September 1952. This was located along both sides of the south end of Birmingham Street, but also had departure stands in adjoining Fisher Street and Porters Field. The departure point for Service D40 and Service D41 moved from King Street to this new site on Saturday 18th October 1952, with outbound buses running via Castle Street, The Broadway, Ednam Road, St James Road, and Trinity Road to Wolverhampton Street, before resuming the existing route.
On Saturday 3rd June 1961, BMMO revised their local Dudley network with most routes seeing a reduction in frequency. The Saturday evening frequency on the combined Service D40 and Service D41 timetable between Dudley and Gornal Wood was reduced from every 20-minutes to every 30-minutes at this time.
BMMO's involvement with most routes in Dudley ended on Sunday 2nd December 1973, when operation of all local Birmingham and Black Country services, including Service D40 and Service D41, passed to West Midlands Passenger Transport Executive (WMPTE) from the start of business on the following day.