货物列车紧急制动距离延长对通过能力的影响

Research on Impact of Lengthening Emergency Braking Distance of 120 km/h Freight Trains on Carrying Capacity

120 km/h货物列车紧急制动距离从1400 m延长到1600 m,相应的常用制动距离也要延长,这涉及信号机布置、列车操纵、车轮踏面损伤、对通过能力影响等许多方面,是一个十分重要的技术问题。本文首先检算了120 km/h货物列车不同条件下的紧急制动距离和常用制动距离,根据制动距离确定闭塞分区长度,根据闭塞分区长度采用牵引计算的方法确定追踪列车间隔时间,从而判定紧急制动距离延长对追踪间隔时间的影响。同时,还采用牵引计算的方式确定紧急制动距离延长前后的列车停车附加时分,计算停车附加时分延长对通过能力的影响程度。认为120 km/h货物列车紧急制动距离放宽到1600 m后,闭塞分区计算长度要增加70 m,这对新线信号机布置有重要影响,既有线不满足要求的,需要限速,或者改造。同时还造成货物列车90 km/h初速时紧急制动距离超过800 m,新车和既有货车的制动率不一致,当新旧车混编时会加剧列车纵向冲动。因此建议对《铁路技术管理规程》这一条款的修订应慎重。

When lengthening the emergency braking distance of 120 km/h freight trains from 1400m to 1600m, the normal braking distance of them also needs to be lengthened. That is an important technology problem which involves signal installation, train control, wheel tread damage, impact on carrying capacity and other aspects. In this paper, the emergency braking distance and normal braking distance of 120 km/h freight trains in different cases are calculated. The length of the block section is determined according to the braking distance. The headway is obtained by the method of computation of train traction based on the length of the block section. Then the impact of lengthening the emergency braking distance on the headway is decided. The additional stop time that relates to lengthening the emergency braking distance is obtained by the method of computation of train traction. The impact of the additional stop time on carrying capacity is quantified. When the emergency braking distance of 120 km/h freight trains is increased to 1600m, the calculated length of the block section is prolonged by 70m. It has important influence on the signal arrangement of new lines. Those existing lines which do not satisfy requirements have to be upgraded or limited in speed. The emergency braking distance of the freight train at 90 km/h exceeds 800m. Because the braking ratios of new and conventional freight cars are different, longitudinal impulses of trains will be aggravated when they are mixed in one train. It is suggested that it should be cautious to revise the terms of lengthening the emergency braking distance in ＂Railway Technology Management Regulation＂.