New Structural Design of Modern Tramway Track System

Since the 1880s, as a form of urban public transport, the tramway track system has been widely used in large cities in Europe, North America, and Asia. The design prototype of the modern tramway track structure was first developed in France in the late 1990s. With the successful operation of modern European trams on the tramway track system with a new structure, trams have re-entered people’s sight. Their environmental protection, energy-saving, comfort, and flexibility characteristics make them a new trend in the development of public transportation. This article will focus on introducing the latest structural design of the modern tramway track system.

The Role of Tram Track in the Modern Tramway Track System

Guide

The primary purpose of tramway track design is to guide trams so that trams can run along the tram tracks. The tram has no steering controller similar to the steering wheel of a car, and its operation depends on the tram track to guide. When a tram is running on a curved section, the tram wheels mounted on the bogie at the bottom of the tram will impact the tram track, and the fixed tram track will force the tram wheels to turn in the direction of the rail, thereby guiding the tram in the direction in which the track extends. In the straight section, the fit relationship between the tram track and the tram wheels limits the lateral movement of the tram to a certain extent, thereby preventing the wheels from slipping out of the track.

Reduce the intensity of the load

The load of the running tram is transferred to the track through the tram wheels and then transferred to the roadbed through sleepers and ballast. Due to the continuous expansion of the force acting surface during the transmission process, the pressure transmitted to the roadbed is greatly reduced, so the roadbed with limited bearing capacity will not be significantly deformed. The concentrated load on the tram track is generally greater than 60kN, the rail surface compressive stress exceeds 40,000kPa, and the uniform load strength finally transmitted to the top surface of the roadbed generally does not exceed 100kPa.

Vibration and noise reduction

In the modern tramway track system, the rubber pads between the tram track and the rail sleepers, as well as the ballast with ballast track structure have a certain degree of elasticity, which has a certain effect on reducing the vibration of trolley and tramway track structure. The noise caused by wheel-rail friction can be reduced by improving track smoothness and rail surface smoothness.

Modern Tramway Track Structure

Although the tramway track has been widely laid in various countries, due to different core technologies, the tramway track structure adopted by different countries is also different. According to the material for laying tramway tracks, there are mainly two types: ballasted track and ballastless track. According to the presence or absence of fasteners, it is divided into a tramway track structure with fasteners and a tramway track structure without fasteners. The common tramway tram track structures are as follows.

1. Translohr tramway track structure

The new Translohr tramway track structure was developed by the French Iohr company and has been laid in France, Italy, and Tianjin and Shanghai of China. This kind of tramway track structure adopts a rubber wheel guide rail system, and its main feature is that only one guide track is used for guiding. The standard length of the guide track is 12m and the weight is about 28kg/m. The guide track is fixed by resin material instead of the rail fastener system and fixed in the guide track groove reserved for the concrete pavement by special primer treatment and resin casting. The width of the track groove is 190mm and the height is 90mm.

The new Translohr tramway track structure mainly includes a guide rail, cast-in-place epoxy resin, triangular foam filling block, insulating pad block, and reserved concrete pavement. The tramway track structure is relatively simple, the construction period is short, the cost is low, and the noise is low.

2. Double block tramway track structure

Some tramway track lines in the Netherlands use a double-block tram track structure. From top to bottom, the tramway track structure mainly consists of tram tracks, truncated-filled composite materials, asphalt layers, concrete slabs, fasteners, under-rail pads, sleepers, and lower foundations. The tram tracks and sleepers are connected by fasteners, similar to the traditional railway connection. The tramway track line has better flexibility and adjustability.

3. Assembled tramway track structure

The assembled tramway track structure is mainly composed of groove rail, rubber boots, trackbed slab, and filling materials. The most prominent feature of this tramway track structure is that the tram track is placed in the rubber boots, thereby greatly reducing the lateral impact of the track structure, and the effect of vibration and noise reduction is significant. The prefabricated concrete slab is laid between the tram tracks, which is efficient and convenient for construction, and the maintenance and repair work in the operation process is relatively simple.

4. Embedded tramway track structure

Embedded tramway track structure is the most commonly used tram track structure, which is mainly divided into two types of structures: cast-in-place and precast track slabs. This kind of tramway track structure cancels the traditional railway fastener system and uses polymer filling materials to fix the tram track, making the track structure simpler and more convenient for construction. However, the laying cost of this kind of tramway track structure is relatively high, the maintenance is relatively difficult, and it is not easy to adjust the track geometry once there is a problem.