They took one of the three huge pusher tugs, the Diamond Mine.

By late 1864, the prototypes were operational, with the stern section replaced by a pusher tug.

Most have been superseded by pusher tugs.

The Large Pusher Tugs, all three of them, were thrusting hard against Moon Ten.

"We can use one of the Large Pusher Tugs and the first two kilos of antimatter-a mere anticantaloupe, Rachel-to bust it loose and put it on course for the L5 point.

By the time Bartholomew had obtained a patent on 7 February 1862, the plans had developed somewhat, as the design now included a steam-powered pusher tug instead of the stern compartment, and included chains which ran the length of the train to enable it to be steered.