Learn about Glued Insulation Joint with Us

Glued insulation joint is one of the track parts made by a special process. It is mainly used for insulated track circuits and railway turnouts on the seamless railway line.

Types of Glued Insulation Joint Bar

Rail glued insulation joint has two types typically. One is hot glued insulation joint, and it has the characteristics of high strength, reliable insulation performance and long service life. The other is on-site cold setting glued insulation joint, and it is convenient to be transported and has a low cost.

Factory-made glued joint: In the factory, through heating (or under normal temperature), the gluing process is used to connect two rails to joint bar, the insulating trough (or insulating cloth and adhesive), the insulating end plate and the insulating towel and glued and fastened into the insulated joints with high-strength bolts.

On-site glued joint: on construction site, the glued insulation joint bar is glued to steel rail with the adhesive, and fastened into glued joint with high-strength bolts.

Rail glued insulation joint realizes the effective division of track circuits in the station area. It can restrain the axial temperature force of long rails completely, and provide the transmission of temperature force of turnout section, which can reduce the impact force of wheel and rail, improve the service life of the rail and the running speed of the train. At the same time, it can effectively control the noise of rail transportation.

Making Process Analysis of Rail Glued Insulation Joint

Rail glued insulation joint is affected in product quality by production process in addition to the influence of the adhesive material itself. Through the comparison of technical performance of two kinds of joint materials and products, it is obvious that the technical performance of hot glued joint is higher than that of cold setting glued insulation joint.

Glued surface treatment

The glued surface treatment is extremely important. Oil, rust and even oxide film affect the wetting, rheology, diffusion and penetration of the adhesive, and the gluing effect ultimately. Hot glue is factory-produced, provided with equipment and working conditions for implementing clean treatment of rail and joint bar. The sandblasting machine can be used to polish 100% of the gluing surface of the workpiece to be bright and clean. The cold setting gluing operation is carried out on site. It can only be polished by manual tools such as grinding wheels or gauze. It is difficult to polish rust and oil on the surface. In addition, the conditions are poor in the open air, and there is sand, rain and dust pollution.

Regulation of heating and heat preservation

Hot glued joint factory adopts automatic temperature controlled equipment in production. The heating rate is adjustable, the temperature is constant, and the distribution is uniform. But cold setting glued insulation joint can only be done by using simple flame heating, which brings us uneven heat distribution, lack of temperature quantitative detection and control means, and difficult heat preservation process not to hardly be realized. The holding time is difficult to be guaranteed, and sometimes the adhesive is not fully glued, and the circuit has to be opened, affecting the shearing strength and glue toughness of the joint.

Human factor

Hot glued joint is made by standardized production with fixed processes and workers. Each process is completed under controlled conditions according to specified process parameters, so the production efficiency is high and the quality is stable. On-site gluing operation is a temporary task in maintenance. The operators are not fixed, and the process is affected in operation by the environment and the human factor, and the quality is unstable.

Reasonable Design of Rail Glued Insulation Joint

Reasonable designed glued insulation joint should meet the following requirements:

• Within the joint range, steel rail shall be able to withstand vertical and lateral impacts acting on the train as it passes through other parts. That is, under the load, the shape and size of the rails in the range are the same as those of other parts.
• Under the action of temperature force, rail seam with the glued joint does not change, or the deformation is controlled within the allowable tolerance, and the joint can transmit the temperature forces reliably.
• Glued insulation joint must be insulated reliably and withstand high voltage, which can meet the insulation requirements of track circuit at the joint and the breakdown caused by high voltage reflow in the electrified section.