Thinking a little about physics and why you can’t just put tracks and ties on bare ground is that I believe that the heavy train cars and locomotives actually float in the ballast and having the right geometry and the right grade of ballast stone is important to the efficiancy of the operation.
I’d say it’s more like a matter of spreading the weight around. Think of the difference between walking in deep snow or walking on top of deep snow wearing snowshoes.
“Float” may not be quite the right term, but you are right that the ballast provides many benefits. Such as alignment control (vertically and horizontally), drainage (when properly graded and kept clean), horizontal stability during temperature fluctuations (especially important in welded rail).
Direct fixation can do much the same but there are trade-offs. It is much more rigid and more difficult to adjust and much less forgiving.
I’m sure Mudchicken can expand on this too.
“float” -NO
Fewer voids as a wheel set goes over and cycles - YES…And then there is the mudmonster (where I think you are getting the floating idea from)…with the sub-ballast and subgrade contributing to the pumping action.
Ballast and its presence is necessary to many, modes uther than just railroads. Each ‘mode’ has learned over time that scrimping on ‘ballast’ (ie: a rock underlayment) can lead to cascading road repair bills.
One specific example was the Pennsylvaia Turnpike (I-80) was uilt on a former railroad ROW;way back when! Esentially, the roadway slabs were laid/poured(?) on a thin base of aparently, the former Railroad’s own ballast.(?) It used to be said; there were two seasons in Pa. Winter and Construction… Driving it was at times, interesting. Following another truck one would notice that the slabs would rock back and forth; when the slab was ut from under the preceeding truck, there would be geysers of water, shooting up i the air as the slab settlled back down… As M.C. would say, another repair for the ‘highway bubbas’ to rework… So not only ‘mud monsters’ under railroad ROWs; THey seem to migrate to the highway systems, as well.
When it comes to land transportation routes - the surface the vehicles travel upon is only the frosting of the cake that begins with a well engineered and compacted subgrade that takes into account all the variables of soil conditions that the route traverses. Once the subgrade is completed the next engineering obstacle is to properl
Actually the Penn Turnpike is I-76. Interstate 80 runs thru northern Pennsylvania, on a more direct New York-Chicago route. I have taken that route many times. The Penn Turnpike joins the Ohio Turnpike, and eventually I-80 also joins the Ohio Turnpike, which then takes on the I-80 designation.
samfp1943 The example of the PA Turnpike being built on the roadbed of the South Pennsylvania RR is incorrect. It was not. It’s correct that the abandoned right of way was purchased by the Turnpike Commission but for the most part the Turnpike was not built directly upon the roadbed. You can check the wikipedia entry for the South Penn for that information or a better source with detail is Harwood’s The Railroad That Never Was. That book is an excellent source of information on the subject. The best thing to do is to get someone else to drive while you sit with the book and pick out the locations along the Turnpike where you can see some of the original roadbed as Harwood does a great job of describing the spots that are still visible from the road. I thought it was easier doing this westbound rather than eastbound on the Turnpike.
I think Sam is mixing up his Turnpikes: the only one that goes near I-80 is the Northeast Extension (which we used to get to Wilkes-Barre in the early '60s). People think the South Pennsylvania was intended as a super railroad with modern grading: it was not, and I suspect there wasn’t anywhere near either the ballast and drainage for the autobahn-style road. Even one of the larger tunnels built for the automobile road has subsequently been ‘routed around’.
To say the track is ‘floating’ would imply displacement… which is not the case. If we understand ‘floating’ as not physically secured to supports (as, for example, cat bridges are assumed to be) then in a sense the track floats on a bed of ballast and is lined and surfaced by moving and tamping the rock. The fact that you can see even well-maintained track ‘breathe’ slightly as HAL trucks run over it sequentially indicates it is not “fixed”. We’d have to take up a slab-track system like the successful one in the Class 9 Research Report to get to concerns like those mentioned with pavement slabs…
When I first went to Louisiana, I couldn’t drive I-20 from Shreveport east to Minden (when driving up to Springhill) because all the slabs were tilted – the near ends would get hammered down as the subgrade slowly subsided; this would give a ramp effect to tractors and trailers which would then hammer down the near end of the next slab in line, so you were constantly going up 20’ ramps and then BANG. There was apparently a similar problem on I40 west of Memphis that necessitated breaking up the entire concrete structure for quite a few route miles – you could see them banging away at it with Trackhoe-mounted air hammers. Concrete ties were quite bad enough, thank you!
Parts of I-81 are built on the old “Valley RR” R-O-W between Staunton and Salem, VA.
Parts of NY17/I86 are built on the former ROW of the NYO&W.
As I recall it, a few years before the approaching US Bicentennial and the completion of today’s I-80 across central Pennsylvania, some influential person(s) decided “76” would be perfect for the Penna. Turnpike’s Interstate number.
But in Ohio, I-76 was being built east from Akron to link up at the Ohio - Pennsylvania line with today’s I-80. From what I heard from knowledgeable people at the time, the new Interstate from Akron to the Hudson River was to be named I-76. The Ohio Turnpike and the Penna. Turnpike were supposed to have the same number, I-80. But the Penna. Turnpike folks saw a branding - marketing opportunity and decided “I-76” had to be the Penna.Turnpike eastwards from the Ohio line. After all, it was already complete, unlike I-80.
Thus, to this day there are dozens of confused eastbound drivers everyday in Ohio on I-76 who’d like to go straight ahead east to NYC, but the signs indicate that’s another road, “I-80,” and now I-76 goes to…Pittsburgh? Philadelphia? Really?? While drivers on I-80 (the Ohio Turnpike) now find they are on I-76? Where’s my Garmin or map?
How long ago now and how important does the Bicentennial and “76” stuff seem? Who remembers when Pennsylvania put a Liberty Bell image on its license plates? Or how silly it was to see billboards on the Penna. Turnpike welcoming one to “Pennsylvania…where America begins”?
I-80 in Pennsylvania was supposed to be I-76.
Upon further reading I see that the Penn Turnpike was indeed to be designated I-80. However, the northern PA corridor that eventually became I-80 was designated I-84 before the alignment was settled. After the alignment was moved further south to the present I-80, then what became known as I-84 ended westbound at Scranton.
And yes I have noted that the connection between Ohio Turnpike I-80 and the I-80 continuation to the east seems like an afterthought, as if they wanted you to continue on the tolled Turnpike.
The first time I drove I-80 thru PA in daylight (late 1970s) I was suprised how many rail lines I crossed in such an unpopulated part of PA. There seem to be a lot fewer now.
There were a lot more coal mines then, too, the likely reason many of the lines you saw existed.
Don’t forget the shared right-of-way of the South Shore Line and the Indiana Toll Road between Hammond and Gary. South Shore had the r-o-w lined up in the late 1920’s but the Depression intervened. The Toll Road Commission was trying to line up a route through Northwest Indiana and South Shore suggested the solution that came to pass.
MidlandMike
The first time I drove I-80 thru PA in daylight (late 1970s) I was suprised how many rail lines I crossed in such an unpopulated part of PA. There seem to be a lot fewer now.
There were a lot more coal mines then, too, the likely reason many of the lines you saw existed.
Tree 68 is correct. The closing down of the coal mines was the final straw that eliminated some of the rail lines that inhabited the area. Also, besides being saving many miles if you are traveling from Chicago to NYC and southern New England, the current I-80 has good scenery all across PA–unless you are not a fan of mountains, valleys, and trees everywhere. Traveling on it during its peak Fall color season is a delight to the eyes.
Back in the brief window of time railroads still had the money to contemplate a high-speed railroad between New York and Chicago, there were two proposals to construct what were essentially bridge lines across that area. Both would have involved multiple long tunnels and mandatory electrification to work.
One was the Ramsey (yes, the same one as in Ramsey, NJ) who surveyed a high-speed route for the Gould interests between 1903 and 1906 (it was torpedoed by the Panic of 1907 and the problems Gould had with financing thereafter). This was actually revived in the late 1920s with the promise of extensive foreign capital (there is apparently a detailed route survey filed with the ICC in 1930!) but you can guess where it went.
The other was a PRR proposal that was either ordered or conducted by Sam Rea (and named after him) that came to light around the early 1930s. This diverged from the ‘main line’ around Lewiston and went nearly straight east, well north of the Pittsburgh area, then presumably across Ohio and to a connection I believe in Fort Wayne. Improvements on the already-fast PRR line west of Fort Wayne might have resulted in close to 10-hour time, the same as promised by the stillborn C&NYAL in roughly the same timeframe as the Ramsey survey.
Would have been interesting to see the super railroad connecting east under the Watchungs…
Yes I know about the coal, but a number of the lines were thru lines rather than just coal branches, like the NYC line west of Beech Creek to Ohio, the PRR Low Gradient line, and their Allegheny River line which went thru oil country.
That’s a bit of a myth.
It first comes up in April 1963, well before anyone started thinking about the Bicentennial.
The renumber was tied to the construction of I-79. The Pennsylvania Secretary of Highways was concerned that having a north-south interstate that passed through I-80N and I-80S would be confusing (and you and I both know it would have been). I-76 was first mentioned in the letter to AASHO about the 80N/S confusion: “New route number (I-76 for reference, but number to be assigned by AASHO) from point B (Pittsburgh) through points C (Monroeville) and D (New Stanton) to point E (Bellmawr, N. J.), 320.9 miles.” You may note that this segment means that west of I-79, it would have remained I-80S. Pennsylvania had already approached New Jersey about the renumbering and they were on board. The first signs went up later that year. In February 1964, Pennsylvania went back to the AASHO “asking” for what was already inevitable from the start: renumber I-80S in Ohio as I-76.
Judging from the context, it appears to have been selected for no other reason that it had to fit between I-70 and I-80. If one assumes that Pennsylvania always assumed that Ohio would be forced to renumber I-80S, and that’s a reasonble one to make because they’
Floating does bring up slightly off topic. The new Kansas City (MCI ) airport tarmac was built on a swamp. Often after rains you would see water jumping out of the cracks when airplanes taxxied along. The streach out when terminal renovations occurred had water jumping out on all the cracks for every pile driver pounding. Cockpit joke was wonder if the ferry boat was going to sink when traveling on a slab.
How it is now have no idea.