After crossing the main ditch
the line entered an unlined tunnel cut through solid rock that
extended beneath the Triton Fountain, Triq Sarria, Wignacourt's
Fountain to the underground
station at Floriana which was 850 yds. from the Valletta entrance.
During the construction the line had to be amended to take account
of an unmarked subterranean reservoir and the resulting "S"
curve produced a less than pleasant effect on the passengers.
The 1000 yds. long tunnel
had a falling gradient, towards Museum station, of 1 in 65 and
was excavated from three access shafts along the line which were
later used as ventilation shafts. The setting out, by the resident
engineer, was so accurate that break through of the headings
was achieved with an accuracy of 1in.