Ballast Types

NW Modeling List nw-modeling-list at
Fri Jun 10 13:35:26 EDT 2016

Thanks Dean.

I pulled out my father’s 1929 Railway Engineering and Maintenance Cyclopedia today.  I remembered it having a good coverage of ballast types, but didn’t recall if it addressed some standard form of “grading”.  Turns out it doesn’t, but it did rank different materials (Eric’s comment on slag reminded me of the article).  For my purposes, I’ll assume numbers 1 and 2 below would be considered Class #1, number 4 Class #2 and number 8 as Class three.


The AREA Committee on Ballast studied the comparative merits of ballast material and offered the following views at the 1929 convention:

Ranking on comparative merits:
1 - Stone - Broken stone is the best ballast for heavy, high speed traffic.  Keeps track in line well, drains very well, resists fouling, but can be reused after cleaning (every three years on coal carrying lines close to mines), and has low dust (good for passenger traffic).  First cost is high.
2 - Washed gravel - When prepared correctly, is good for heavy, high speed traffic.  Fouls quickly and cannot be cleaned - so must be replaced with new ballast (three to seven years, spending on load and proximity to mines). Drains well.  Cost of maintenance such as surfacing is less costly than stone, but requires more frequent attention as it has a tendency to “creep” out from under ties.
3 - Slag - Broken or crushed slag varies greatly in hardness, with some being the equal of broken stone.  Others are too soft, and will break down under tamping and will begin to hold water.  Granulated slag drains better than sand, but has high cementing values, making it hard to maintain.  
4 - Screened gravel - If gravel is screened it is usually also washed.  If unwashed, it retains too much dirt (which promotes vegetation and doesn’t drain well, is dusty and muddy) and is not economical for use except for yard or side tracks.
5 - Pit run gravel - Quality varies greatly.  Exceedingly difficult to drain, fouls soon leading to expensive maintenance.  Where the deposit is free from dirt and loam and not too much sand, it drains well and can give satisfactory service for light traffic, and makes a good sub-ballast.
6 - Chatts (material obtained from the tailings or waste from the concentration of zinc, lead and other ores) - Limited to areas close to the source. Zinc chatts is coarser than lead chats, so drains better and is considerably less dusty than the very fine lead chats.  Considered economical where better material is not available.
7 - Burnt clay - Use is limited to a very small area.  It is recommended that the item be eliminated from classification (of a ballast material).
8 - Cinder - Low cost since the only expense is haulage.  Drains well when new, but disintegrates rapidly.  Suitable for side tracks of lines with light traffic or for track on unstable roadbed (excellent sub ballast in wet roadbed conditions).  Very easy to work, making it ideal for small track forces.  Cinder quality is higher if they are cooled with water immediately after dumping, rather than being allowed to burn.

Matt Goodman
Columbus Ohio

On Jun 10, 2016, at 7:05 AM, NW Modeling List <nw-modeling-list at> wrote:

From my experience just what I have seen in researching the bluestone branch. I think that No2 is a mixture of smaller stone and cinder mix i hope this helps. .. Dean Taylor

On Jun 10, 2016 6:40 AM, "NW Modeling List via NW-Modeling-List" <nw-modeling-list at <mailto:nw-modeling-list at>> wrote:
Hello List,

I’m looking through a reprint of the N&W Standards Drawings, specifically ballast sections.  The drawings show the ballast sections for tangents and curves (as well as single and double track) with “Class #1” ballast and a separate profile for “Class #2 or 3” ballast.

I’ll assume Class 1 is crushed rock; what is Class 2 and 3?  My guess is 3 is probably cinder and 2 is maybe gravel, but they're just that, guesses.

Any idea?  Or should this go to the main list?

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