brianthesnail96 said:
I'd think it unlikely that in reality the van would be placed at the front of the train by the loco, regardless of predominant upgrades. As well as providing braking on downhills, a brakevan is also used to prevent runaways, if the train was to break in the middle the rear portion could be brought to a controlled halt by the brakevan.
BTS96 is correct. On non braked or partially braked trains, the brake van is ALWAYS at the rear in case the train becomes divided into two or more portions, the runaway wagons can be contained within the train and/or the rear portion can be brought safely to a stand. The brake van can also be used to rub the brake thus keeping the couplings tight on downhill grades preventing a snatch in the dip before a following uphill grade which could break the train.
On fully brake fitted trains, as long as the brake van is also fitted or has a through pipe, it can be marshalled anywhere.