Post Office Railway 1927 Stock

These trains were the original rolling stock on the Post Office Railway which began operating in tunnels below London linking major railway termini and post sorting offices. Ninety of these units were built which typically operated in trains of two or three [1]. Each unit carried wheeled trollies which could contain mail bags, these were loaded or unloaded at the various stops on the Post Office Railway.
Preserved unit 601 at Mail Rail


Information
Number built: 90
Built: 1927
Builder: English Electric
Motor: English Electric (440v DC third rail)
Power: 22 hp (16 kW)
Wheel arrangement: 4wRE

Unfortunately the original rolling stock had a number of drawbacks which became apparent soon after the railway began operating in 1927. As the units had a fixed wheelbase this was causing excessive wear and tear on the unit's own wheels and on the track. This resulted in increased power consumption [2]. The system was already becoming overwhelmed with the amount of mail being carried.

The 1927 Stock was replaced within a couple of years by the 1930 Stock which consisted of two smaller powered units either side of a mail carrying wagon. These articulated units solved many of the problems with the original stock. Many of the 1927 Stock's internals were reused in the replacement 1930 Stock including the motors, axles and wheels. One unit of 1927 Stock has been preserved.
A train of 1927 Stock in operation [3]


Side view of 601, notice the hatches to the mail carrying compartments

Another view of 601


Loading mail trollies [4]


[1] Mike Sullivan, Mail Rail (Redshank Books, 2019) p. 19
[2] Peter Johnson, Mail by Rail (Ian Allan, 1995) p. 118
[3] "London's Post Office Tube Railway", Meccano Magazine (October 1928) p. 812
[4] E. Flaxman, "New cars for London P.O. Tube Railway", Meccano Magazine (June 1930) p. 463