I'm not sure this follows.  A bike might be less efficient than a boat at that speed - for a start it would have vastly more surface area (and hence drag).  We could imagine trains powered by teams of fit peddlers (peddling their bikes :) sitting inside a hollowed out locomotive.  But then why not power them by electric wires coming from whatever source is cheapest (under whichever metric you wish).

However you are presuming that bikes are efficient for locomotive power, they are not.  They are efficient for moving people, but for moving cargo I expect wind or solar to be a better option (including embodied resources).

An idea I tried to promote on a disused rail line between two towns which had a fair amount of freight exchange was to buy a few rail container wagons, cover their roofs in solar panels, with a controller to connect to a motor.  Each wagon would be self powered, whirring along at whatever speed it could achieve (perhaps 5km/hour) travelling to the other town.  It could then provide pretty much free cartage.  Of course it would be too slow, and there were all sorts of objections with respect to safety, vandalism, theft, transloading, cost, getting stuck under bridges.