Now you’re dealing with the whole foundation, not just the fastener. Apparently, you don’t look at the out of face maintenance problems when dealing w/ concrete & steel ties, either when they fail (plenty do) or when a wheel gets on the ground and chews up the OTM. The track programs on the major railroads are an involved science (and art) that is doing pretty well in a brutal environment, given what resources they have to work with.
Plenty of failed experiments are out there on the R/W in the weeds. Keep the ones that work and are moderately economical and move on.
Hey, I served an industry like that. About 700 feet of track to their building, and the one trainmaster counted about 80 gauge rods on it. Siding was on a pretty good curve.
Something to be said here about wood and wood preservation.
Creosote an older traditonal wood preservation process used wood-tar or coal-tar as a base. Coal-tar is the modern usage and defined by the AWPA - American Wood Protection Association as derived from pure bituminous coal and given a standard P1/P13 and P2. Currently the process must be done under license of the State Departments of Agriculture and is only a pressure treat process.
Another common modern treatment of wood is with copper, chromium and arsnic salts which often turn the wood green and often called Wolmanized CCA. These mineral salts render the wood useless as food for fungi and pests. They also do not leach easily from the woods into the enviornment. This and other processes are classified by the AWPA - American Wood-Preservers Association which does extensive classification for industrial application.
Woods desired for Wolmanizing are,
Pines - Southern, Ponderosa, Red, Jack, Lodgepole, Sugar, White, Radia and Caribbean
Coastal Douglas Fir
Western Larch
Stika Spruce
Redwood
Woods are are often knowen for their unique properties and uses. Oak is the steel of hardwoods and White Oak the strongest. Other hardwoods like Walnut make fine cabinet woods and gunstocks. Maple is the white furnature wood as is cherry. Although not common any of these I am sure have become railroad ties at some point in history.
Among the softwoods, Fir is the most desired for structural building accept where light weight is required where Stika Spruce is used. Pines lack the integrity of the others but are the more common.
I’ve been reading Camp’s “Notes on Track” the last couple of weeks and it is amazing how the discussion in this thread is discussed in his book written over 110 years ago. Examples would be spikes versus screws, wood vs other matrials for ties, how little is required of a tie on tangent track…
The main difference now is that trackwork is highly mechanized.
BaltACD
Recently observed a local yard track that a tie gang had recently ‘serviced’. New ties placed every 3rd or 4th tie, tie plates in place - NO SPIKES.
FRA Track Safety Standards for Class 1 track - poor condition, 10 MPH max. speed, etc. - allow the distance between “good ties” with adequate spikes in tangent track to be as great as approx. 100 inches = 8.3 feet (5 good ties every 39 ft. = 468 inches, with at least 1 under any joints; 6 ties in curves over 2 degrees). That’s roughly every 4th or 5th tie. For Class 3 track (40 MPH freight speed), it’s 8 ties per 39 ft. (4.5 ft. average center-to-center spacing, roughly every 2nd or 3rd tie) in tangent and curves up to 2 degrees; 10 ties per 39 ft. for curves over 2 degrees (4 ft. average spacing, practically every 2nd tie).
In tangent track, if the ties are providing good vertical support/ bearing for the rail (so it won’t twist or roll outwards), and the rails are fairly large (so they won’t twist or bend sideways too much), spikes in every 4th or 5th tie are all that are really needed for a minimum operation (low speeds, not too many trains, etc.). When constructing new track, that’s how it’s done (though every 3rd tie in curves) - then the intermediate ties are spaced and spiked, before the ballast is dumped in. The rest of the ties and spikes are to distribute the train forces and loads over more ties and provide more support and margins of safety - which is also more economical because the lower loads extend the life of the tie
See what I mean ? Just that fast, there are 2 examples of what I was saying.
Although this thread is about the number of spikes in a tie, it may as well be about the ties. Here, the ties are a kind of ‘surrogate’ for the spikes: spikes are worthless without a tie, and a tie needs a number of decent spikes in order to perform its function as well.
Even Trains’ “Professional Iconoclast” from some years ago - John Kneiling - liked to point out that more time could be saved by removing slow orders, minor (inexpensive) improvements of the track alignment, automating interlockings, improving/ removing grade crossings, etc., than by upgrading to really high-speed track (expensive to do and maintain), or buying a lot of high-horsepower locomotives, etc.
There’s an opportunity here for a professional/ academic paper of the business school sort about the risks and benefits of concrete ties, and managing that technological risk (compare with Michael Bezilla’s book, Electric Traction on the Pennsylvania Railroad: http://www.psupress.org/books/titles/0-271-00241-7.html ; see also his paper:
THE DEVELOPMENT OF ELECTRIC TRACTION ON THE PENNSYLVANIA RAILROAD, 1895-1968
A few years decades back, concrete ties were a promising technology, but not yet fully developed and proven.
So Chief Engineers were faced with a dilemma: Invest on a large scale in an unproven technology which might save a lot of money, but might also be a dud; or,
Skip it all, but that might mean a lost opportunity to save money, and letting competitors get ahead.
The consensus seems to have been to invest in concrete ties, and pay for any needed fixes (as now) later, when they do occur.