The Royal Limited: Second LineExpansion

From BoardGameGeek:

Business is booming! Running two lines on parallel tracks allows for maximum profits, as long as there are enough passengers. Second Line is a 4-card expansion for The Royal Limited that introduces additional train cards in a new color and allows players to operate a second train below their first line. To play with the Second Line expansion, shuffle all train cards together to begin. Draw one additional card each turn and place cards into either row following the normal rules. Beware: the new grey train cars can only accept passengers that match the number (as well as VIPs). Keep your trains close in length, as you'll lose automatically if one is too far behind when the game ends.