This often involved unhitching the tow line, but on some canals they were constructed so that there was no need to do this by placing the two ramps on the same side of the bridge (see middle photo), which turned the horse through 360 degrees.
On the Macclesfield Canal this was achieved by building spiral ramps and on the Stratford-upon-Avon Canal and others by constructing roving bridges of iron in two cantilevered halves, leaving a slot in the middle for the tow rope.
The Birmingham Canal Navigations has many examples, mainly of cast iron, which took the towpaths across factory arms.
The ramps of the bridge are typically studded with alternating rows of protruding bricks to prevent the feet of the horse from sliding.
The bridge may be constructed of cast iron (particularly in industrial areas) or of more conventional brick or stone.