Patent GB-848143-A (GB)
Title: Improvements in or relating to the construction of railway tracks
IPC: E01B9/22
Filed: 1958-05-23
Abstract: 848,143. Securing and insulating railway rails. BREVETS INDUSTRIELS S.A. May 23, 1958 [May 27, 1957], No. 16648/58. Class 104 (2). A method of constructing railway tracks comprising the steps of filling the joints between mutually abutting elements of a rail track assembly with an initially liquid or plastic filling material and then curing the filling material which will then solidify, will not appreciably contract and will have compressive and shear strengths not substantially less than those of the joined elements but a considerably lower tensile strength. In the arrangement shown in Fig. 1 the structure on the left-hand side of this Figure illustrates the conventional method of attaching the sole plate 8 to a sleeper 6 by bolts 9, a rail 1 to the sole plate 8 by spikes 7 and the fish plates 3 to the rails 1 and 2 by bolts 12, and the structure on the right-hand side of the Figure utilizes the method of the present invention in which the bolts 9 and 12 and spikes 7 are omitted and their function is superseded by bonding the various members in mutual contact. The bonding material is placed between the sole plate 15 and the sleeper 6, the fish plate 3 and rail 2 and at 5 between the rail ends. An anti-creep device 13 is driven into . the sleeper through an opening in the sole plate 15 and is bonded to the rail 2 and an anti-creep device 14 is driven into the sleeper 6 alongside the lateral edge of the sole plate 15 and is bonded to the rail 2. A metal strip 4 overlying the gap between the rail ends is inserted in a recess in the rail top and is bonded to the rails 1 and 2. In the initial stages it may be necessary to utilize the bolts 9, 12 and the spikes 7 to hold the parts together until bonding is effected and then to remove such members. In some constructions the bolts may be left in place after the bonding has been effected. In the arrangement shown in Figs. 10 and 11 the rails 101.and 102 are heated to about 60‹ C. and the fish plates 104 to about 40‹ C., the filling material is spread on the surfaces of the fish plates and between the rail ends and the fish plates are then bolted to the rails; the temperature difference between the fish plates allowing the fish plates to be driven deeper into the rail channels than would normally be the case. After the joint is assembled the whole assembly is heated to cure the filling material which takes three to five minutes to cure at 180‹ C., 5-10 minutes at 150‹ C. and 36-48 hours at 20‹-25‹ C. To obtain electrically conducting joints the surfaces of two conducting members such as 1 and 2, Fig. 2, are roughened so as to provide contacting high spots 16 and the members coated with the filling material 17 are then pressed together by a bolt 12. The bolts 12 in this instance may be left in position but if the filling material used forms a strong metallic bonding they may be removed. In an insulating joint, Fig. 4, a flanged tube 18, such as resin bonded glass fibre, is completely embedded in the filling material 17. The bolt 12 is coated with a material, e.g. dipping in a silicone bath, which will facilitate removal of the bolt after the filling and bonding material has been cured. In the arrangement shown in Fig. 5, in which conventional anti-creep devices 10 are fitted to the flange of the rail 1 the interior of the jaws of the anti-creep device is coated with a filling material and the device is then driven home in the usual manner so that some of the filling material remains in the layer between the faces of the device 10 and the rail 1 whilst the bulk of the material is squeezed into the space at the end of the jaws. The filling material may be of thermo-setting synthetic epoxy resin or, mainly constituted by a reaction product of epichlorohydrin, magnesium cement or a cement having a complex thorium oxysulphochloride base. The filling material may also contain ground cork or sawdust, mineral powders, metallic particles, vegetable mineral or metallic fibres, and may incorporate shims in cases where the joint spaces are unusually wide. Any convenient heating means may be employed such as electrical, infra-red radiation or a naked flame from a welding torch.