Bishop's Bridge and Harrow Road Bridge
Bishop's Bridge is built in brick, with two uneven spans, one large enough to take barge traffic. The red brick has weathered well and its appearance used to contrast favourably with the concrete Ha'penny Foot Bridge further along the canal, near St Mary Magdalene Church, which was of surpassing ugliness. The Ha'penny bridge has now been replaced and there was a plans to rebuild Bishop's Bridge. We shall hear of this later.
At this point the canal narrows to reduce the length of the bridge and has a towpath on either side protected by railings. In 1910 only one towpath was open to the public, but later the whole pedestrian use of the Basin was altered.
The original bridge was built of steel box girders which were formed by rolling steel plates into Z shapes. These were hot riveted to steel plates to form a row of hollow boxes shaped like a bar of Kit-Kat chocolate. The bends in the design make the beams stiff and very strong for their weight. The original bridge girders of 1801 were small in size as this was the limit of the rolling machines then available.
1939 Emergency Canal Gates
In 1939, when War was imminent, the Paddington canal was in danger from bombs. If the canal wall over Paddington Station was breached, the water in the canal and the basin would flow down to Paddington Station and all the low-lying areas near it. Barnes Wallis was later to invent the bouncing bomb to destroy the dams in the Ruhr valley. Here in Paddington was a similar danger, so emergency gates were installed in the canal. at intervals. The theory was that any sudden rush of water would jerk the doors shut and only the water between a pair of gates would be lost. Failing that, they could be closed by hand.
The pair below Harrow Road Bridge, built to close off the water from Little Venice, are still in place, forgotten, and a silent reminder of 1939.
Earlier there must have been similar gates to close off the Basin so that it could be cleaned. Each year empty barges were drawn into the Basin. The gates were closed so that no water from Little Venice could get in, and the Basin water was drained off. This was possible because the Basin was high up and the water could flow into the sewers below.