By April 1991, the CP had taken over operations on the D&H and was using regularly using their M630s and M636s on trains 555/556 between Montreal and Saratoga Springs, but did not yet regularly venture further on the D&H. On this day, CP M636 4717 led 556 to Saratoga Springs as usual. The power south from Saratoga Springs was SD40-2 5682 and RS18u 1810. In a move that I suspect was unusual, M636 assisted all the way to Mohawk Yard, but was then attached to a ballast train (trailing two CP RS18us) and returned to Saratoga Springs. 556 continued from Mohawk with just the lead two units.