Work began at East Boston in late 1836 ; it reached Lynn in the spring of 1837 .
Construction was slowed by the Panic of 1837 and did not reach Salem until 1838 .
Work began at East Boston in late 1836 ; it reached Lynn in the spring of 1837 , but construction was slowed by the Panic of 1837 and did not reach Salem until 1838 .