{TAIL ~ The single line} in the system is designated with two reference characters 19 a and {HEAD ~ 19 b} to signify which side of the platform the line is connected to 
{ TAIL ~ The single line } in the system is designated with two reference characters 19 a and { HEAD ~ 19 b } to signify which side of the platform the line is connected to
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH