1. Department of Civil Engineering, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113, Japan, Telephone: 81/3-3812-2111, Ext. 6120, Telefax: 81/3-5689-7268,
2. Railway Technical Research Institute, 2-8-38, Hikarimachi, Kokubunji, Tokyo, 185, Japan, Telephone: 81/425-73-7261, Telefax: 81/425-73-7248,
3. Department of Civil Engineering, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113, Japan, Telephone: 81/3-3812-2111, Ext. 6122, Telefax: 81/3-5689-7268,
4. Institute of Industrial Science, University of Tokyo, 7-22-1, Roppongi, Minato-ku, Tokyo, 106, Japan, Telephone: 81/3-3402-6231, Telefax: 81/3-3479-0261,