In total 106 bridges cross the navigable River Thames below Lechlade. Of the 76 on the non-tidal section, 13 are railway bridges, 46 are road and 17 are footbridges. The lowest is Osney Bridge in Oxford with a height (headway) of only 2.28m (7'5"). The highest bridge is the Maidenhead railway bridge at 9.80m (32'2"). The first bridge upstream is the Halfpenny (or Town) Bridge at Lechlade which marks the practicable start of the navigable part of the River. It was built in 1792 by James Hollingworth. The last bridge before the start of the tidal Thames is the footbridge across the lock cut at Teddington. On the tidal Thames there are 30 bridges of which 9 are rail (2 have footpaths attached), 19 are road and 2 are footbridges. The lowest headway is at Hammersmith which is only 3.70m (12'2") high and the highest is the Queen Elizabeth II Bridge at 54.10m (177'6"). Tower Bridge has a headway of 8.60m (28'3") or 42.5m (139'6") with the bascules up. All types of bridges (beam, cantilever, truss, arch and suspension) are over the Thames. Similarly there is a mixture of materials with bridges made from wood, brick, stone, cast iron, steel and concrete. The oldest bridge over the non-tidal River is at Radcot and was built in 1225 ( but is now over a side stream). The oldest bridge over the navigable section is at Newbridge which, with its six arches, was built c.1250