Always generate a north->south trip index.
Always generate a north->south trip index.

edmundnoble/pebble-caltrain,dwfreed/pebble-caltrain,edmundnoble/pebble-caltrain,ashneo76/pebble-caltrain,Katharine/pebble-caltrain,wowza512/s,edmundnoble/pebble-caltrain,edmundnoble/pebble-caltrain,dwfreed/pebble-caltrain,dwfreed/pebble-caltrain,ashneo76/pebble-caltrain,ashneo76/pebble-caltrain,wowza512/s,dwfreed/pebble-caltrain,Katharine/pebble-caltrain,wowza512/s,Katharine/pebble-caltrain,ashneo76/pebble-caltrain,wowza512/s,Katharine/pebble-caltrain