Glad to hear it went back on relatively easy a a thrown track is usually a real PITA.....not to mention they usually happen in the absolute worst place you can imagine to work on one.
That said, a tip for future refference. You can usually eleminate the need for a jack on the older machines with enough hardwood blocks. What you do is put the blocks under the rear of the machine, first making a good base, and then stacking them as high as possible. If you can get them to touch the bottom of the machine that's great. The placement will depend on the way the machine is balanced, the lay of the land, etc, but typically you want to stack as close to the side your wanting in the air as possible. Once you get it blocked then put the blade on the ground and apply enough down pressure to lift the machine. What will happen is the machine will pivot on the blocks and lift the whole side, drive sprocket included, off the ground. In a case like your talking about, with soft ground, a good foundation is a must, but it it will still usually take a time or two of lifting and reblocking to get the foundation blocks imbedded in the ground as far as they want to go, and for the stack to become solid. Once you get the back up you can either block the front to keep it up, even if the blade drifts, or simply keep the machine running and keep adjusting as it drifts. Either way you can maintain the complete side of the machine, and therefore the whole length of the track off the ground without using any tools other than a few hardwood blocks. Working on equipment for a living I've done it many, may times over the years and have only had a small handfull of machines where it did work, and most of those were the newer ones. Good luck next time.