By 2005 the JiTong line had come under pressure to move more traffic across its system with fewer delays. As diesels ousted steam from the Tongliao - Chabuga and Daban - Haoluku sections, some of the surplus engines were redeployed to enable most trains over the Chabuga - Daban section to be double headed. Loads were limited by the length of passing loops so the double headed trains weren't much heavier than the singles and would really fly. By autumn 2005, the fleet was down to 23 QJs and there were no spare engines on busy days. As a result, some heavy trains would have to be single headed due to a lack of available power. While the double headers took the hills in their stride, single engines had their work cut out. QJ 7037 was working flat out as it passed the busy crossing at Xinlongdi, east of Diaojiaduan, with an eastbound freight on 8 September 2005.