Regarding the suitability of steel mill slag for ballast, I believe it was reasonably good ballast until the advent of the 100 ton car. It was fairly well fractured like good quality crushed rock, so it locked together well. For the Q and other midwestern roads, it was probably better than the alternative, which was limestone. Although limestone is a good building material, it is inferior to either granite or basalt when used as ballast. Once any ballast breaks down into finer particles which then trap water, the track structure then becomes hard to keep in surface. The track begins to pump, particularly under joints, and railroads in the 60's still had lots of jointed rail when the 100 ton car came into heavy use.
The mannix sled was mentioned in previous posts on this subject, and one advantage of the sled was that, in addition to clearing out all of the old fouled ballast, it tended to improve the subgrade somewhat. Since it was pulled under the track and ties, it was under a certain amount of weight, so it would smooth out and compact the subgrade a slight amount. One of the keys to a good track structure is a smooth solid sub-grade that does not retain water.
In the 1980's and 90's, the centennial cutoff from Needles to Maxwell was suffering from severe surface problems. When continual light surfacing with good clean ballast did not solve the surfacing problem, some exploration of the subgrade was conducted, and they found areas where the original subgrade had completely failed, and there were deep pockets (10' to 12' under the track) full of slag ballast and trapped water.
Glen Haug
To: CBQ@yahoogroups.com
From: CBQ@yahoogroups.com
Date: Tue, 16 Jun 2015 10:27:03 -0700
Subject: RE: [CBQ] Re: CB&Q Facilities, Vol. 2 Questions [1 Attachment]
[Attachment(s) from jeralbin@aol.com [CBQ] included below]
The steel mill slag ballast I remember being loaded into scores of CB&Q Ballast hoppers at Illinois Slag and Ballast, was a very light gray (almost white) and extremely porous. This was in 1962-1967. They called it pop-corn slag. The molten slag came from International Harvester's South Chicago steel plant at 106th and Torrence Ave. directly to IS&B's elevated slag dump. There, they dumped the slag thimbles down the elevation. The molten slag was continually drenched with high volume water sprays. This caused the slag to puff up full of steam induced air holes. A large electric shovel worked the cool side of the elevation loading large chunks of slag into small dump cars. Short trains of the dump cars would be pushed by a small "critter" to the crusher/screening plant and out came ballast. I have been told that slag ballast made very poor ballast. It has been said that the slag was pounded into powder in service and then into mud when it rained. I have attached a photo of the IS&B dump.
Regards...Jerry Albin, Homer Glen, IL
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Posted by: GLEN <glenehaug@msn.com>
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