western Railway, which controls its link, has no P7 with it. BRC has only P4 and P5, and since P5 are surplus, they go along with this super crawler.
As for halts, the weight of this train is so less (courtesy no AC class+short rake) due to which even P5, with its low TE can haul this train effortlessly. It reaches to its maximum speed in almost no time with this train, trust me :)