Step 5

def main_menu
	puts "List train lines (T)? List Stations (Sta)? Quit program (Q)?  Please make a selection."
end	

loop do
	main_menu

	answer = gets.chomp.to_s

	if answer == "T"
	puts "The (L) Train, The (N) Train, The (S)ix Train"

	elsif answer == "Sta"
	puts "The (L) Train, The (N) Train, The (S)ix Train Choose a train line by letter."
	selection = gets.chomp.to_s

	if selection == "L"
		puts "You selected the L train."
		puts "8th Ave, 6th Ave, Union Square, 3rd Ave, 1st Ave, Bedford Ave"
	elsif selection == "N"
		puts "You selected the N train."
		puts "Times Square, Herald Square, 28th St, 23rd St - HMH Nexus, 
		Union Square, 8th Ave"
	elsif selection == "S"
		puts "You selected the Six Train."
		puts "Grand Central, 33rd St, 28th St, 23rd St, Union Square, Astor Place"
	else
		puts "That's not one of the choices."
	end	

	else answer == "Q"
	puts "Thank You"
	break
	end		
end

Great! Next step, pay attention to your indentation to make sure your code visually represents its structure!