We've all seen photos from 100 or more years ago, showing men with teams of horses grading a future railroad ROW. Once they heaped up the prairie to the correct height, and leveled it, how was the dirt compacted to carry the weight of a train without uneven settling?
Thanks to Chris / CopCarSS for my avatar.
Even today, the first trains over a section of track which has had the roadbed disturbed will travel at a reduced speed, in part so they can help the roadbed settle in. I'd opine that such was the case in the situation you present.
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
I have never seen any mechanical compactors in use during the horse scraper/manual labor phase of excavating which was used on most pioneer railroads; nor during the steam shovel phase which came into existence around 1890, and was used to realign many pioneer railroads.
With horses and scrapers, you would get some compaction with the hooves and with the wheels on some scrapers and haul wagons.
The steam shovel phase used a steam shovel to cut and fill trains of dump cars. The fills locations had temporary trestles built over the low spot and the trains transported the dirt from the steam shovel cut to the fill site and dumped off of the trestle. The trestle was buried in the process, and left in the fill.
That kind of filling would not get any compaction. I assume that they mostly simply lived with the lack of compaction or insufficient compaction, and raised the track incrementally over time to compensate for fill settling.
Too much water makes soil uncompactable, and filling temporary trestles over water bodies left the fill saturated and completely uncompacted. I don’t know how they stabilized that without a long delay to allow for some drying and settling.
West of Minneapolis they double tracked the Milwaukee Road main line in 1914 by adding a second track encroaching into Lake Hazeltine. When the track was finished and surfaced, they put it into use. It looked perfect, but the saturated fill was not stabilized to carry the load. The first train was an eastbound passenger train. When it hit the new fill, the track went all out of alignment and the cars lurched every which way. At least one passenger jumped out a window. Eventually the engine derailed and scalded the engineer to death.
The weight of a train would provide some compaction to a new fill, but proper compaction requires compacting the fill in layers called "lifts," which might be a foot or so thick. You cannot get proper compaction by filling the entire height and then compacting from the top.
Even with modern compactors, proper compaction can be difficult to achieve due to the fill being too wet.
That is interesting Bucyrus... I have only had one experience with this, but my experience is contrary to what you say... I had a gas leak in my front yard once and the gas company took up the sod in a 4x6 area and then dug a hole about 4 ft deep (the pipe was only about 18 inches down) to give room for the welder (a brave soul to say the least!) to seal the holes in the pipe and re-wrap it in tar paper.
They piled the dirt in the grass next to the hole. Most of the hole was dug with a small back-hoe and the rest by hand. When they were ready to refill the hole, one of the men asked if I'd be willing to fill the hole with water first. I asked why and he said that otherwise I'd have a big mound of loose dirt there that would take a long time to flatten out, if it ever did. He then said that if I removed the mound then it would, over time, settle and I'd have a big dip in the yard.
I did as he suggested and when the hole was about half full of water they started pushing the dirt back into the hole, both using the backhoe (sideways) and by hand (edit: I mean using shovels... these guys were nice, but not THAT nice!) to scrape the dirt off the grass where it had been piled. They got all the dirt back in the hole without much in the way of pushing or shoving it down and not much water spilled out of the hole as the dirt was put back in.
Then they rolled the sod back over it and said I should water it every day for a week or so. The area was fairly flat when they were done and to this day (oh golly, 35 years later!) the lawn shows just a slight dip there (I happened to drive past the old place just a few weeks ago).
The dirt was a sandy clay with just a couple of fist sized rocks and bigger clumps of hard dirt. I think it is called "Sandy Loam" but not sure about the real name for the type (former Iowa cornfield).
From that experience I would have thought that using wet dirt for fill would be a good thing to use. But like I said, that is based on ONE experience.
Semper Vaporo
Pkgs.
(1) lotsa hooves in front of the fresno - Eh?. (somebody has never seen a sheepsfoot compactor, eh CAT makes a really good one)
(2) old railroad loadings were about a third or less of present day expectations.
(3) Failures in the early days were fairly common and were manageable
(4) Also then as now, train movement added to the compactive effort and trains back then were a lot slower.
(5) Geotechniical science and Carl Tergahzi had yet to catch up with the construction boom.
RAILROADS HAD BIGGER ISSUES TO DEAL WITH.
mudchicken2) old railroad loadings were about a third or less of present day expectations.
Bringing up a question I've been meaning to ask. What degree of compaction do they currently expect for large earthen fill areas?
Let's say they were going to build a 25' elevated class one freight railroad across a flat metropolitan area, and the project was to be built with concrete bridges spanning the city streets, but with long areas over dirt between those bridges. What level of compaction would they want?
mudchicken (1) lotsa hooves in front of the fresno - Eh?. (somebody has never seen a sheepsfoot compactor, eh CAT makes a really good one) (2) old railroad loadings were about a third or less of present day expectations. (3) Failures in the early days were fairly common and were manageable (4) Also then as now, train movement added to the compactive effort and trains back then were a lot slower. (5) Geotechniical science and Carl Tergahzi had yet to catch up with the construction boom. RAILROADS HAD BIGGER ISSUES TO DEAL WITH.
Semper VaporoFrom that experience I would have thought that using wet dirt for fill would be a good thing to use. But like I said, that is based on ONE experience.
Well if there was a dip left after backfilling, the backfill must have been more compacted than the soil before the hole was dug. Water jetting is a common technique to settle soil, but it is not satisfactory for compaction to a specification. For proper compaction of the hole, you would fill about 8 inches, level it off, and then tamp it down. Then fill another 8 inches and tamp that.
And in addition to that technique, the soil must have the proper moisture content. Moisture lubricates the particles so they squirm around and align themselves with the least amount of space between them. But too much moisture surrounds each particle with a film of water which prevents the particles from getting into contact with each other.
Flooding the backfill with water saturates the soil so that it will slump together and eliminate large voids, but leaves it too wet for the particles to contact each other and consolidate as tightly as they should.
But in the case of digging a hole in your yard, the issue of compaction is not critical as it would be in a roadbed or under a foundation. So the water jetting method is sort of a poor man’s compaction that is good enough. If they gas company digs a hole in the street, they backfill in separate lifts and compact each one with a powered tamper.
For railroad fills, I suspect the pioneer railroads had adequate compaction from animals and wheels if the soil was not too wet. In the course of digging up soil and grading it into a fill, the compaction develops gradually as the surface activity on the fill continues.
Not only does moisture both aid consolidation and hamper compaction, but also, compacted soil is less able to absorb water than loose soil. If it happens to rain when spreading loose fill, the relatively uncompacted surface of the fill will get saturated, and become impossible to compact sufficiently to meet the specification. It must be either left for several days to dry, or be removed and placed elsewhere so the filling can continue with soil having the proper moisture content.
I don't know how common they were in railroad ROW construction but there were horse drawn compactors, both rollers and drag beams. The rollers seem to have seen the most usage in agriculture and also in treating snow covered winter roads. In the latter case very large rollers were pulled by teams of draft horses and compacted the snow to make a more passable surface for other horse drawn vehicles (AFAIK, the highway snow plow didn't come along until the advent of motor vehicles though, of course, the RR's used plows well before that)..
"I Often Dream of Trains"-From the Album of the Same Name by Robyn Hitchcock
I would think that both rollers and sheep's-foot tampers would have been able to be pulled behind teams of horses, mules, or oxen.(My grandfather was a teamster in the truest sense of the word...the foundation for the first house my parents owned--they built it themselves, too--was dug by Grandpa Shaver and his teams.)
Carl
Railroader Emeritus (practiced railroading for 46 years--and in 2010 I finally got it right!)
CAACSCOCOM--I don't want to behave improperly, so I just won't behave at all. (SM)
Semper Vaporo Then they rolled the sod back over it and said I should water it every day for a week or so. The area was fairly flat when they were done and to this day (oh golly, 35 years later!) the lawn shows just a slight dip there (I happened to drive past the old place just a few weeks ago). The dirt was a sandy clay with just a couple of fist sized rocks and bigger clumps of hard dirt. I think it is called "Sandy Loam" but not sure about the real name for the type (former Iowa cornfield). From that experience I would have thought that using wet dirt for fill would be a good thing to use. But like I said, that is based on ONE experience.
A: They were filling a small contained area inside a compacted hole, not building a grade.
B: You did not drive heavy equipment like a train over it regularly.
C: It still developed a small depression.
The comparison is not relevant. Perhaps a better comparison is how they build new or extended runways on an airport. They not only do the multiple compactions, but they then let it sit for months and compact it again before they pave it.
Dave
Lackawanna Route of the Phoebe Snow
When filling the hole, you were filling a confined area. The water helped the dirt particles find their niche, then drained away into the surrounding soil.
If one side of the hole had been open (ie, on a hillside), the technique would not have been as successful, as the weight of the dirt above it would tend to squeeze out the previous fill from the side.
So, too, I suspect, would be fill in the lake situation.
I would imagine that the first fill into a body of water would be rip-rap, then smaller rocks, and finally gravel/soil.
We run across a large fill that began life as a long trestle. The trestle was built specifically to reach a source of fill on the "other end" of the area to be filled. They took the top off a hill. When a state bridge inspector looked at the trestle, he noted that he could only approve it for a couple of year's use. The railroad acknowledged, and pointed out that by then the trestle would be completely covered with fill, which it was.
I would opine that the simple act of dumping fill 60-70 feet (or more) would offer a certain amount of compaction of the lower levels. In addition, the vibrations of the trestle from trains running across it would likely also help settle the fill.
This particular fill is about 140 years old, and is holding its own quite well.
Our A&WP sub was built before the civil war and has a 50 MPH limit for the whole route from ATL - Montgomery. In front of my house is a wet area that I suspect was not compacted. Although the A&WP sub is mostly a ridge runner it crosses many streams and goes thru some swamp areas either active or drained.
I have been told that surfacing on the sub is more often than other routes even though traffic is not as heavy as the other routes..
blue streak 1 Our A&WP sub was built before the civil war and has a 50 MPH limit for the whole route from ATL - Montgomery. In front of my house is a wet area that I suspect was not compacted. Although the A&WP sub is mostly a ridge runner it crosses many streams and goes thru some swamp areas either active or drained. I have been told that surfacing on the sub is more often than other routes even though traffic is not as heavy as the other routes..
Optimum moisture content is dependent on the soil, but is usually 8-10% in most places. (if it has a lesser moisture content, the 6 inch layers of dirt fail like onion skin because they won't bind. Too much moisture = mud and voids) There have been ASCE/ASTM compaction standards out there using standard or modified proctor molds and hammer drops for 50+ years. PDN and I could explain it, but we'd put you all to sleep. Suffice it to say, dirt goes in and is almost always in excess of its 95% maximum calculated compaction.
They call it "engineered fill" for good reason.
I've known some long term construction types who claim they can tell to what degree a site has been compacted, merely by walking over it.
Convicted One I've known some long term construction types who claim they can tell to what degree a site has been compacted, merely by walking over it.
I think there is some truth to that, but in commercial construction a compaction degree is specified, and it has to be tested to prove that the specification is met. Not only is there specifications for compaction, but there are specifications for the soil type. The type of soil can affect its performance independent of the compaction. Clay can be compacted, but it is highly expansive if it gets wet. But then it is hard to get it wet if it is compacted enough. But then again, it is also highly expansive if it freezes, and that expansion can uncompact it, so it gets wet easier.
Sugar sand has particles all the same size, so it cannot be reduced in volume much by compaction. And even when fully compacted, it is loose, so if you load it in one spot, it rises up around that spot. This makes it an unstable base for laying pavement on top.
Crushed rock with a blend of different sizes, including fines, is highly compactable for creating a high load bearing and stable base. One such blend is called Class 5. It is a very specifically controlled blend of crushed particle sizes in specific proportions. The largest rocks in Class 5 pass a ¾” sieve. The smallest particles in the blend are dust.
Another highly compactable material is pit run gravel with a small amount of clay. The clay particles are the smallest. The gravel is a blend of different size particles from pebbles down to sand.
Bucyrus but in commercial construction a compaction degree is specified, and it has to be tested to prove that the specification is met.
One individual in particular that I recall, had been building tilt-up buildings in the San Francisco area for like 40 years, a wealth of information to be sure, but so full of himself that it was often a chore just being nice to him. He'd come walking onto a jobsite and (among many other things) tell you what level of compaction you had based upon the feel he got through his boots.
Knowing him, he probably was right far more often than he was wrong, but he just worked so hard at being a total PITA whenever he was in the mood to "share". It used to tickle me how EVERYONE who dared disagree with him was a moron, mentally challenged, or a crook.
Does the seat of your pants / sole of your shoes compaction, diagnostic equipment have a bigger margin of error as the soles on your shoes wear thinner? Wasn't it Jack Benny, who said the soles on his shoes were so thin, if he stepped on a dime, he could tell you if it was heads or tails?
Was there a set compaction rate, or target, on railroad ROW's built a century, or more, ago?
Murphy Sidingsole of your shoes compaction, diagnostic equipment have a bigger margin of error as the soles on your shoes wear thinner
He was fond of 'spiking' his heel down into the surface, when challenged, and then say "Oh really? well look at that" as if everyone would regard the dent that was left as some form of benchmark.
In the grand scheme of things, wouldn't a guy only be able to gauge the compaction level in about the top foot of soil anyway?
I think you're correct.
Murphy Siding Once they heaped up the prairie to the correct height, and leveled it, how was the dirt compacted to carry the weight of a train without uneven settling?
Murphy,
I avoid commenting on many technical issues because of my ignorance. When it comes to compaction, however, I am only almost totally ignorant. I have many years of experience compacting the soil around my tomato stakes.
Would I embarrass myself if I suggested that in the early days railroads used techniques not far removed from my own tomato stake techniques? Probably by 1840 they had left my knowledge far behind.
Amtrak is shortly going to replace its concrete ties around New Brunswick, NJ. The reports don't talk about issues like compaction. They run one of there big machines over it and there are new ties and new rails. It is all so simple. At least it is simple to completely ignorant guys like me.
But the fact that you railroad guys make it look so simple is a real tribute to your expertise.
John
John WR {SNIP} But the fact that you railroad guys make it look so simple is a real tribute to your expertise. John
{SNIP}
PS Murphy,
I have been to New Jersey Transit's RiverLine station in Bordentown, NJ. Bordentown was the original terminal of the Camden and Amboy; the station is on the Delaware River and, when traveling from New York to Philadelphia, you transferred to a boat they to complete your journey.
When the C&A was build Robert Stevens arranged to buy square stone sleepers quarried at the New York State Prison in Ossining, New York. You can still see then where they were set for the original rails. After over 180 years they have not sunk below the surface of the soil but are quite visible with a few inches projecting about the soil. Perhaps even then they had a little more understanding of compaction than my tomato stake knowledge.
Link to a decent article and photo of a 2-horse Fresno scraper:
http://kingsriverlife.com/08/14/the-fresno-scraper/
Another decent article - an summary of modern methods - "How to Select a Soil Roller - An overview of compaction technology":
http://www.gradingandexcavation.com/GX/Articles/How_to_Select_a_Soil_Roller_8467.aspx
- Paul North.
Gentlefolk, mention has been made of sheepsfoot rollers, both ancient (horse drawn) and modern (self-propelled.)
Have you ever wondered why they have that name?
Looking at some military engineering books from the 19th century, it was recommended that the sheep acquired for feeding the troops should be run back and forth over freshly-mounded earthworks. (The same books noted that the sheep would keep grass trimmed to military height around powder storage structures...)
So, have a compaction problem? Just call in your neighborhood shepherds to run their flocks across the fresh fill.
In this, 'Everything has to be machinery," age, we tend to forget that the practical use of four-legged critters was common knowledge in the past.
Chuck
Murphy Siding In the grand scheme of things, wouldn't a guy only be able to gauge the compaction level in about the top foot of soil anyway?
http://armyengineer.tpub.com/EN54537/EN545370102.htm
Better yet, see the reference source from which it was taken - an Army training manual on SOILS ENGINEERING at: http://armyengineer.tpub.com/EN54537/index.htm
Convicted One Murphy Sidingsole of your shoes compaction, diagnostic equipment have a bigger margin of error as the soles on your shoes wear thinner He was fond of 'spiking' his heel down into the surface, when challenged, and then say "Oh really? well look at that" as if everyone would regard the dent that was left as some form of benchmark.
I do that often as a check to verify the mechanical test results in stone. If they hit the optimum moisture during compaction, it shouldn't leave a mark. Even 100% compacted aggregate will displace under foot with no moisture to hold it together.
Soils, on the other hand, vary in density, and respond differently to compaction due to make-up, so the "heel test" is very inaccurate.
Murphy Siding We've all seen photos from 100 or more years ago, showing men with teams of horses grading a future railroad ROW. Once they heaped up the prairie to the correct height, and leveled it, how was the dirt compacted to carry the weight of a train without uneven settling?
Many, maybe most, railroads built in the US were "developmental" railroads. This was especially true for rail lines built out in to the prairie.
The idea was that if you made transportation available economic development and settlement would follow. Then the railroad would earn a return for its investors by providing service to a newly developed area. It generally worked, although the construction contractor often wound up owning the railroad because the original promoters ran out of money and couldn't pay him.
In such a situation they didn't worry too much about details such as proper compaction. The idea was to just get trains running. The line was then upgraded as business developed.
There was a rapid divergence of rail technology and construction in the US as compared to the UK. In the UK lines were built to connect established population and commercial centers. In the US the lines had to be built to create population and commercial centers. Big difference.
The US lines also had less access to capital. So they were built cheaply and upgraded as warranted. It worked. We got the best rail system in the world as a result.
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