Not only battleships and tramcars but railway passenger carriages have been known as dreadnoughts.
The UK Great Western Railway had various cars, made around the turn of the 19th/20th. century and the Metropolitain Railway which ran in the London area also had a dreadnought or two.
A preserved GWR car is at Didcot : www.didcotrailwaycentre.org.uk
and details of the the Met one are at : www.vintagecarriagetrust.org