of the 2nd Indian Cavalry Division in 1916 shows a lot of vehicles in the background which look like gun limbers or ammo wagons to me, each drawn by a team of six horses. It would seem odd to me to put a huge number of limbers into a queue, so my guess is these wagons are for ammo supply?
Looks like a standard field artillery limber to me so most likely for resupply, doesn't look like a piece that would usually be on its own except without the gun
