It was constructed with difficulty by embanking the river and raising the level of the formerly marshy ground, and was opened in 1858.
The subsoil was composed principally of clay and sand, and the railway had to be carried over the moss on the level, requiring cutting, and embanking for upwards of 4 m.
Large quantities of embanking were sunk in the moss, and, when the engineer, George Stephenson, after a month's vigorous operations, had made up his estimates, the apparent work done was sometimes less than at the beginning of the month.
The walls are embanking walls, with a low breastwork in places.
Above it is an embanking wall of irregular masonry, and below it some remains of Roman baths, including five parallel vaults of concrete.
It is almost entirely an embanking wall, as is the rule in the cities of this part of Italy, with a maximum height, probably, of about 30 ft.