They settled technical problems arising in the normal operation of newly-made subway train and its serial production.

They also perfected stationary and mobile rail butt-welders in a technical aspect and made a breakthrough in laying non-point of contact rails and high-speed track.

At the Kim Jong Thae Electric Locomotive Complex, researchers completed miniatures of 10-odd buildings and promoted the modernization of production processes.

They are now working hard to solve the sci-tech problems arising in speeding up the construction of Hyesan-Samjiyon broad-gauge railway.