It's about a mile from the southern exit of Bramhope tunnel to Horsforth station, a matter of minutes on the train currently. I can't see how it can be feasible for a service to stop at both stations, I doubt a 170 would even get up to speed in that distance before having to slow down again. If they are doing 2tph then I assume that's 2tph stopping at LBA and 2tph stopping at Horsforth with the turnback service filling in the gaps for Horsforth. I've no idea how they are planning to get 4tph to LBA without increasing the Harrogate line trains to 6tph or just bypassing Horsforth completely.