Real ballast, amazing variety

[Biased turkey]

I went down to the local railrod track in St. Laurent ( a suburb of Montréal ) , picked some real ballast sample within a square meter area ( a square yard for our friends south of the border )
And gues what ? none of them looks alike ( I'm not a geological expert )
I always tgought that the blallast used in a track come from the same area, but obviously it doesn't.
I'm puzzled

 

[Cannonball]

I've never really paid much attention to it recently.
The two most common I've seen are granite and some pumus looking stuff.
Never quite the mixture you have there though.

 

[Biased turkey]

I'm puzzlzed because the rock with the red arrow is really very porous ( spelling warning ) and light , like a volcano rock ( as far as I know there is no volcano in Québec ) while the stone with the blue arrow is like a regular stone with some pigeon **** ( sorry, but it's the best way to describe it )
Any geologist lurking around here ?

 

[Cannonball]

Pumus stone (volcano rock) is hauled in from all over. You'll find it thousands of miles from any volcanos.

 

[Russ Bellinis]

I think some railroads may buy and haul in all of their ballast from one area, while others buy whatever is the least expensive at the time they need it. Then you get some areas where two or three railroads operate, and you can find anything there. Here in So Cal most of the ballast on the BNSF is red rock, but up on Cajon Pass where the BNSF shares trackage rights with U.P. and the old S.P. main runs parrallel to the BNSF main, I've seen ballast that is speckled. It appears to be ecqual parts of BNSF red and S.P./U.P. grey. By the way, you can find out if the light weight grey rock is pumice by putting it in a bucket of water. If it is pumice, it willl float.

 

[railohio]

The pumice might also be coke shaken from a passing train. It too is porous and light. I can't really tell from the photos posted.

 

[2-8-2]

I'm inclined to agree with Brian. I've looked at several ballast samples during my railfanning excursions, and most ballast I've seen is pretty uniform in size. That may very well be coke.

 

[60103]

The porous rock also looks like cinder (large!) from steam days. Have they changed the ballast in the last 45 years?
I know that in the West Toronto Junction area, CP and CN use very different ballast - one has a light grey and the other dark grey to black. It's interesting to watch it where the 2 roads cross or join.

 

[Knighthawk]

It's always difficult to tell from pictures, but as one of my various hobbies is lapidary arts, I happen to have some geological knowledge. In my opinion, from left to right, what you seem to have there is two different blends of granite, coke, limestone, and what looks like black granite, with limestone inclusions...pretty much the same kind of blend of rocks that we get here in London for ballast. I'd like to know specifically where it comes from, as occasionally you can make some pretty startling finds. Last year, I happened across a golf ball sized amethyst crystal amongst some newly laid ballast. Ordinarily I don't go anywhere near train tracks, but while I was out with some other railfans, watching from a footbridge over the tracks, I spotted a purple glint by the tracks, so after making sure there was nothing coming, (one of the guys had a scanner, and could hear the local dispatcher), I went down and retreived it, and it is now proudly part of my collection.:thumb:

 

[nachoman]

I'm a geologist, and while I can't say what those rocks are from that particular photo, I can say I have noticed the same thing. The vesicular rock could be slag from some kind of smelting or metal production operation. I think it depends on the railroad, and who is in charge at any particular time. Some railroads may be very particular about their ballast and use the same source for their entire railroad for years, or until someone else takes over the job and decides something else is better. I don't think they ever remove ballast. i think they just spread more. Anything that gets removed gets removed naturally or if removed by the railroad is probably just pushed aside rahter than hauled off. Here is what I figure happened - over the years the railroad spread ballast from different sources - using whatever was available at the time. Since the new ballast is just spread over the old, it eventually mixes in and that leads to the menagerie you see now.

kevin