1. Yearbook of Railroad Facts, p. 51. Association of American Railroads, Washington(1980).
2. M. D. Roney, M. C. Turcot and R. W. Lake, Heavy Haul Railways Conference Proceedings, Perth, Australia. Paper B.6. (September 1978).
3. D. H. Stone, AREA Bull. 80, No. 679(1980).
4. S. Bramwell and T. F. McElroy, Heavy Haul Railways Conference Proceedings, Perth, Australia, Paper A.4. (September 1978).
5. P. Curcio, S. Marich and G. Nisich, Heavy Haul Railways Conference Proceedings, Perth, Australia, Paper 1.10. (September 1978).