question: What is the date (to) associated wiht a traction type of electric and the Yarmouth Light and Power Company system?
answer: SELECT date__to_ FROM table_name_38 WHERE traction_type = "electric" AND name_of_system = "yarmouth light and power company"
context: CREATE TABLE table_name_38 (date__to_ VARCHAR, traction_type VARCHAR, name_of_system VARCHAR)