This is a common trope. See for example bar075~Daniel O'Connells Steam Engine

Voting in the general election of 1837 began on 24th July three weeks after the opening of the railway. The election was won by the Whigs but Birmingham and its hinterland voted Tory[i].
"We can send them directly over to France" may be an allusion to the Eagle Air Ship, an abortive attempt in 1834 to create a steam powered balloon. (See bar384)
"We will send them by steam to America" may be an allusion to the Great Western the first steamship purpose-built for regularly scheduled trans-Atlantic crossings, ship which was launched on 9th July 1837. (see bar142~The Great Western). Other steam powered vessel had made the crossing before 1837. [iii]

References:
[i] https://en.wikipedia.org/wiki/United_Kingdom_general_election,_1837
[ii] https://www.justincroft.com/book/3119/aviation-european-areonautical-sic/first-aerial-ship-the-eagle-160-feet-long-50-feet/ (accessed 04Feb21)
[iii] https://en.wikipedia.org/wiki/Steamship (accessed 04Feb21)

The physical effort demanded by the treadmill combined with the poor prison diet had severely debilitating effects.
The vertical separators between prisoners working the treadmill can be seen in the illustration above. They prevented prisoners from talking to each other, hence "the silent dodge". Dodge here being used sardonically.

The treadmill at Coldbath prison, Clerkenwell,  London