The comment I responded to did say 'carry'.

'Just dig a trench and fill it with seawater'. Starts to sound an awful lot like a canal to me ... and ... why do you need a train to pull this?

Canales origionly used mules to pull the boats. that today would avoid the props on ship digging up the bottom. Those land based trains can also be electric for environmental savings.

In the Panama Canal ships are pulled by locomotives on rails next to the canal. They have to do that because the canal is too narrow for ships to steer under their own power

That's only true for the locks.

That's the joke