Exchanging rails with Japanese precision

Track possessions on Japanese high-speed lines are short. Tracks are not closed for maintenance works. Rails and sleepers must be exchanged in the shortest possible time. This is why staff, machines, and design engineers must meet particularly high requirement

In 1982, the mainline between Tokyo and Hokkaido was opened for Shinkansen high-speed traffic. For the first time since the Tōhoku Shinkansen of East Japan Railway Corporation (JR East) was put into operation more than 35 years ago, the rails have to be exchanged. The works started in February 2017. They are scheduled to be completed by 2026. Typical of Japan, the works are perfectly scheduled. Due to the busy schedule and high passenger numbers, the time window effectively available for the exchange of the rails, including the travelling time to and from the work site, is maximally 150 minutes.

Welding on narrow-gauge tracks

Together with Nippon Plasser and ROBEL Bahnbaumaschinen GmbH (Germany), Plasser & Theurer supplied the REX-S rail exchange system after two years of development and manufacture. The unit is composed of a tractive unit, a rail loading train incl. an unloading and positioning wagon and an APT 1500 RA fully automatic welding machine.

1,200 m meters of rails are exchanged in two night shifts. During the first, the APT 1500 R fully automatic welding robot welds the pre-deposited long rails within two hours. In the second shift, during a second two-hour night-time track possession, the rails are exchanged and the rail ends are joined by closure welding. Using the REX-S, the length of the rails to be installed was increased fourfold. At the same time, the welding time per joint was reduced from 40 to about 6 minutes.

REX-S Rail Exchange System

The standard-gauge machine of Totetsu is now in regular operation on the Shinkansen line. As early as in 2015, an APT 1500 RA for Japanese narrow gauge tracks was supplied to JR Kyushu. To meet the Japanese track requirements, both machines had to be in lightweight design.

The traditional Japanese welding method is similar to the flash-butt welding process, but uses a gas burner. The innovative electric flash-butt welding process introduced onto the market, a new type of method for Japan, has caused a major increase in performance and quality. To prove the consistently high welding quality during flash-butt welding, the welding machine was tested using rails, which were delivered to Austria particularly for testing. The Japanese Railway Technical Research Institute (RTRI) checked 20 test welds. To test closure welding, which is an integral part of the exchange of rails, a separate test rig was set up in our factory.