Patent GB-1117255-A (GB)
Title: Means for continually and simultaneously surveying and aligning railroad track
IPC: B61K9/08
Filed: 1965-07-19
Abstract: 1,117,255. Track alignment. CANADA IRON FOUNDRIES Ltd. 19 July, 1965 [21 July, 1964, 20 March, 1965], No. 30664/65. Heading B7N. [Also in Division G1] Apparatus for surveying and aligning railway track comprises a reference line establishing system including an infra-red beam transmitter 10 on a forward truck 11, a receiver 14 on a rear truck 19 and a shadow element 28 therebetween on a truck 30 to establish the reference line, and a detection system including the transmitter 10, a receiver 15 mounted with the receiver 14 and a shadow member 26, the beams to the receivers being separated by the receivers being mounted vertically one above the other, and the shadow member 26 being mounted on a truck 20 and connected to a jack 21 and rail clamp members 23 which shift the track transversely until the shadow member interrupts the beam to the receiver 15. The trucks are all urged against the grade rail 24 by springs and the trucks 19, 20, 30 are coupled together by rigid links 33, 34. The shadow element 28 is mounted by movement transverse to the track by a stepping motor 37 and the receivers 14, 15 are similarly mounted for movement by a stepping motor 36. The stepping motors drive the shadow element 28 and receivers 14, 15 alternately in opposite directions so that the shadow element and receiver 14 hunt about the line established by the reference beam. On straight sections of track the reference and detection beams run parallel to the track at a distance D from the grade rail 24. The track alignment is carried out on a tie to tie basis, the reference line being established at each tie and then used to re-align the track at that position. For the alignment of curved sections of the track, the reference line is arranged so that with the track in the correct position the shadow member 26 will again detect the beam at a distance D from the grade rail. Considering a line extending round the track curve parallel to the track and a distance D therefrom the distance of the receivers 14, 15 from this line will bear a constant relationship to the distance of the shadow element 28 from this line since the distances between these members are known and fixed by the links 33, 34. For curved track sections the motors 37, 36 are driven to position the receivers 14, 15 and shadow element 28 correctly in accordance with signals derived from potentiometers driven by infinitely variable cone and roller gearing from one of the truck wheels as it traverses the curve. This gearing is used to control the positions of the members 14, 28 whilst the truck 11 is entering the curve and the trucks 19, 20, 30 are following it into the curve. Whilst traversing a circularly curved track section the members 14, 28 are maintained in set adjusted positions and the gearing is again engaged by the operator when the trucks leave the curved track section. In alternative embodiments the receivers 14, 15 are mounted on a pivoted quadrant member to provide the necessary translational movement, and pairs of shadow members may replace the single members 26 and 28. Also, by use of a suitable switching circuit a single receiver may be used in place of the two receivers 14, 15.