- Take care with your indentation in the case statement - all of the 'whens' from line 49 need to be indented one tab to the left;

- You can simplify your code further here. If the start_line and end_line are not the same, you could have an else statement that works out the number of stops: 
else
  leg_one = start_index - subway[start_line].index('Union Square')
  leg_two = end_index - subway[start_line].index('Union Square')
  total_number_of_stops = leg_one.abs + leg_two.abs
  puts "You are #{total_number_of_stops} from your station"
end

-Add functionality to print out stops the user passes through on route to destination;