The Commissariat (financial control and supplies) and Transport (operation of wagons and animal load carrying) Corps had the following roles:
Supplying:
The victualing of troops (food and drink).
Animal feed for elephants, camels, bullocks and horses (cavalry and artillery horses).
Military stores, and timber for magazines and arsenals.
Wrought materials for gun carriages.
Infantry accoutrements.
Harness,and saddles.
Camp equipage:
Bedding and Quilts.
Diet, clothing and necessaries for European and Native Hospitals.
Logistics:
Boats for transportation.
Hiring of camels and bullocks for transport(for grain and ordnance).
Carriers for the sick (palanquins and dhoolies).
The soldiers of the corps operated forward and were trained to fight when necessary, albeit with a principle focus on defence. They were generally armed with short rifles called carbines and swords. They drove animal drawn wagons, rode animals of various kinds, principally but not exclusively horses, and maintained a record of issues and consumption. Their entire role was based on the financing, supply, and transport of the consumables necessary to maintain a military force in the field.
When operating in the field in the Sudan they were invariably moved as part of the ‘main body’ of advancing troops if in line-of-column (protected by advanced, flanking and rear guards), and if inching forward in a defensive posture they’d generally be at the very centre of a square along with all the animals. At night and when in defence they would again be at the centre of a square whose perimeter was usually marked and surrounded by a fence of thorn bushes known as a Zariba that was cut and dragged into position by native labourers from the camp followers.
The Commissariat and Transport Corps wore a dark blue uniform with white facings and a double white stripe down the outer seam of their breeches/trousers. The buglers of the corps were responsible for making sounds/calls to order the routine of the day when dismounted, and tactical movement when mounted, e.g. ‘advance’, in order that instructions could be heard and understood above the din of any battle going on around them. In very extreme circumstances there were cases when groups of the mounted corps members were gathered together and used as improvised cavalry, although there’s no recorded instance of that during the Sudan campaigns. You can listen to the bugle calls here:
http://www.farmersboys.com/MAIN/Bugles_Calls.htm