The Paris Cannon was a weapon used in WW1 much similar in purpose to the V-1 and V-2 in WW2. The “Paris Gun” fired rounds that scattered widely. Dr. Gerald Bull developed a system using two 16-inch naval rifles that could place satellites in orbit. The problem was that micro-satellites had not been developed and could not withstand the 20,000-G shock at firing.
The differences between howitzer and cannon (field gun) are gun pressures, velocities, and volumes of the delivered round. Howitzer barrels tend to last longer before replacement or relining. That is an important consideration for any army. The longer the tube of the artillery piece makes movement to, around, and back from the battlefield more complicated.
During WW1 and in WW2, there were examples of naval artillery placed on modified railway flatbeds. The most prolific in WW1 were 14-inch naval guns operated by the US Navy and Army as siege guns in Western Europe. In WW2, the Germans had greatest success with 11-inch railway guns adopted from Kriegsmarine stocks and used in Italy. The most famous battery was known as ANZIO ANNIE. The 280-mm cannon was adapted for US Army use after WW2 as what became known as The Atomic Cannon.