1. Institute of Industrial Science, University of Tokyo, 7-22-1 Roppongi, Minato-ku, Tokyo 106-8556, Japan, Telephone: 81/3-3402-6231, Telefax: 81/3-3479-0261, E-mail;
2. Institute of Industrial Science, University of Tokyo, 7-22-1 Roppongi, Minato-ku, Tokyo 106-8556, Japan, Telephone: 81/3-3402-6231, Telefax: 81/3-3479-0261
3. Department of Civil Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan, Telephone: 81/3-3812-2111, Telefax: 81/3-5689-7268, E-mail;
4. Railway Technical Research Institute, 2-8-38 Hikari-machi, Kokubunji-shi, Tokyo 185-8540, Japan, Telephone: 81/425-73-7261, Telefax: 81/425-73-7248,