Table: canada_street_railways
Columns: name_of_system
location
traction_type
date_from
date_to

Question: what is the date for traction type electric with calgary location?
SQL: SELECT "date_from" FROM canada_street_railways WHERE "traction_type" = 'electric' AND "location" = 'calgary'

Question: Which date has date started from 30 Sep 1913?
SQL: SELECT "date_to" FROM canada_street_railways WHERE "date_from" = '30 sep 1913'