1961?
Was this a staged photo to promote restoration of the canal system (if so, neat!)? Because I'm pretty sure canal boats had been diesel since the late 1800's (or steam powered, thee are a couple that have been restored).
The longest tunnel in the canal system is 3 miles... 19th century engineers dug a tunnel 3 miles long under 600ft of English countryside. Amazing stuff.
Cruising the Cut on YouTube has a lot of video on the canal system.