What is happening here is only the front loco has drivers and last guard wagon has guard. Middle locos are controlled by front loco drivers (remotelty using Radio Frequency controllers). So just one set of crew is required for this multiple train combination. And since it doesn't have any loops in between to accommodate it, it is made to run non-stop, and runs at good speed too. Hence the profit! Last month or so, someone had posted a video of the first such train on the route.