| 摘要 |
1,255,871. Railway track ballast levelling machines. BRITISH RAILWAYS BOARD. 23 Jan., 1970 [30 Jan., 1969], No. 5233/69. Heading E1G. The ballast beneath a railway track 2 is levelled without disturbance of the lower layers by means of a machine provided with a track-lifting unit 4 and an adjustable ballast-levelling tool 5 comprising a pair of transverse rotary helical cutters 11, 12 extending at different heights across the track. The levelling tool 5 is carried by a frame 10 which is supported at each side by a pair of jacks 9 controlled partly by a unit 8 associated with a datum wire 7 (or equivalent optical arrangement) and partly by a device 20 measuring the sleeper thickness. The cutters 11, 12 are rotated so as to cut forwardly the leading cutter 11 being of coarser pitch than the trailing cutter 12. Each cutter has, besides its end bearings, a central bearing 14 carrying a fixed plough 15 and from which extend blade sections 16, 17 of opposite hand. The blade sections may be of constant diameter but as shown have small-diameter outer ends to produce a centrally-depressed ballast profile 24. The machine shown has endless tracks 1 for running on the ballast but may be modified to run wholly or partly on the railway track 2. |
