I’m looking for information about what roadbed material is used within a certain geographical area within the US. I stumbled across such information awhile ago but do not remember where. Anyone have any ideas where I can reference??? Thanx…
To make a minor, but critical, distincton:
Roadbed (aka subgrade) is usually native material, seldom moved farther than it can be pushed by a bulldozer or hauled by an oversize dump truck on a haulage road within the construction site. Excavated material from a tunnel, if used for roadbed, is usually used within a stone’s throw of the portal.
Ballast, that nice, sized rock that surrounds and supports the ties, may be hauled some distance if suitable material is not readily available on site.
Limestone is one material that is quite popular for ballast. Sandstone, in general, is unsuitable. In my immediate neighborhood (southern Nevada) the native rock is sandstone. The UP imports limestone from ??? for ballast.
OTOH, a financially strapped shortline, building quickly on a frayed shoestring, might accept the native sandstone for ballast. Hopefully, there might be enough profit to replace it before it crumbles into dust. More usually, the railroad itself will roll wheels-up and vanish, leaving a long scar on the landscape as the only evidence that it ever existed.
Chuck (Modeling Central Japan in September, 1964)
Case in point is the Grand Canyon Railway in central Arizona. The basic ballast for the main track is Kaibab limestone which is along virtually the whole railroad’s length. In places, gray crushed rock has been added from a more distant source as pictured below. I also noted places where the track had some volcanic (rock) cinder (found relatively close to the right-of-way) interspersed among the limestone.
Mid-twentieth-century photographs of Southern Pacific I’ve studied showed that main-track ballast varied by location most likely because the closest/cheapest suitable stone was used.
Regardless, the ballast type will vary depending on the railroad, the location, and the date.
Mark
Limestone used to be quite popular for ballast, but I think you will find that it is no longer used much, if at all, by the major railroads. Most limestones are fairly soft as rocks go, and heavy traffic will round off the sharp interlocking edges from the vibrations. That dust from the rounding off is known as fines, and fouls the ballast so it no longer drains as well as desired.
It can require complex analysis to select a ballast source. A local source may be much cheaper, especially since the transportation costs are lower, but if it has to be replaced twice as often the annualized cost becomes higher. Most short lines have low tonnage and minimal budgets so for them cheap is probably the only reasonable option.
In the old days, many secondary lines and most yards were ballasted with pit-run gravel rather than crushed rock. Cinders were also popular in yards, which solved a disposal problem at the same time. Crushed rock was mostly found only on the more important main lines.
As others posted, the subgrade generally uses local material, although sometimes when a trestle was replaced by a fill it became practicable to haul in better material from some distance away (but still only something like 10-20 miles at most).
John
Pretty much what the others have already said above, except that I often saw cinders on branch lines of the PRR and RDG in this area, well outside of yard areas.
Granite/ ‘‘trap rock’’ is the preferred ballast material, and for an important main line the railroad will haul it up to several hundred miles if there’s no other equivalent closer source. The trap rock from southeastern Pennsylvania and western New Jersey has been hauled by Amtrak as far north as Connecticut, as as far west as Indiana by ConRail.
I understand that the C&NW used a granite ballast known as ‘pink lady’ from a quarry in Wisconsin, but MidWestern members will likely be able to add more than that.
If you have a specific area in mind, stating what it is might help to better focus the other responses to your question.
- Paul North.