to Cabin John, Maryland. The current collector "plow" was mounted underneath the car on a fitting just forward of the rear truck on PCC streetcars. It had two cables with female connectors on cables to attach to matching cables of the car's electrical system. A "plowman" was assigned at each changeover point from overhead trolley wire to conduit to remove the cable attachments to the car and stow the plow, which did not remain with the car and was reattached in an incoming car running on overhead wire. The lower section of the plow "board" was drawn by the moving car within the cavity of the conduit. Because of this usage, many of Washington's streetcars carried trolley poles, which were lowered while operating in the central part of the city; when the cars reached a point where they switched to overhead operation, they stopped over a plow pit where the conduit plows were detached and the trolley poles raised, the reverse operation taking place on inbound runs. The 'pit' here has the meaning analogous to racing circuit pits rather than a depression in the road. In the UK, London had a hybrid network of double-deck trams: overhead collection was used in the outer sections and conduit in the centre. At the changeover from conduit to overhead wire, at a change pit, the process was largely automatic. The conductor put the trolley pole onto the wire, and as the tram moved forward the conduit channel veered sideways to outside the running track, automatically ejecting the plough - the tram was said to be 'shooting the plough'. At the changeover from overhead wire to conduit the process was a little more complicated. The tram pulled up alongside a ploughman, who engaged a two-pronged plough fork over the plough in a short length of unelectrified conduit and into the plough channel underneath the centre of the tram. As the tram drew forward, the conduit channel moved under the tram, carrying the plough into position. The conductor pulled down the trolley pole and stowed it. The ploughman's job was a fairly skilled one because, if he failed to locate the plough fork correctly, it or the plough could jam in the plough channel and cause lengthy delays. Some tram designs required an extra carrier to be located with the plough and these frequently caused problems for ploughmen not used to the design (particularly if