I'll try. In mining, rail is extended in 20 foot sections. The drift, or tunnel, is extended in 6 or 8 foot blasts, each called a round. So it takes 3 or 4 rounds before you can put in a stand (20' section) of rail on permanent ties. Also you need to keep the end of the rail 6' or so back from the face to prevent blast damage.
So, in short, you have to go 20' where there's no rail before you have enough room to put in rail. After you blast and muck to the end of your stood rail you lay a 20 ft section of slide (just regular rail) on it's side on the ties inside the two stood rails. The ball of the slide, what the wheel runs on when right side up, nestles into the web of the stood section and you spike the foot (flat bottom) so it stays tight. One on each side up agin your stood rails.
Then you back up the mucker to the rear of the slides, drop the bucket and it'll just catch the foot of the slides that are sticking up. Shove (easy) them both forward as long as they go fairly straight and level. Now the flanges of the mucker wheels will ride in the web of the slides as they rest on the leveled shot rock. Then go to mucking, although a little more careful because what your running on isn't the most stable. Clean a foot and a half or so then back up and shove (slide) them forward again. After you go as far as you are comfortable with, usually 3 to 5 feet, you pick and shovel down to line and grade(ish) and lay a temp tie or two. Loose spike the slide down to the temp tie to stable it out a little, shove the slide again, and repeat. You do this for the 3 or 4 rounds needed to make room then take a half shift to stand 20' of permanent rail to proper line and grade. Then do it again.
Probably got you really confused by now. PM if you're interested. I enjoyed the life back then but I was a lot younger.
Edit: Slide rail was also old tramp slang for a loan.
Thank you,
MrSmith