How much do railroad tracks move day to day?

Factual Questions
1

How much do railroad tracks drift around from one day to the next, or as the years go by? The rails themselves, and the points where the individual lengths of steel join, I mean.

I use an old and very lightly traveled railway running through the woods as a set of reference points in a surveying projects. I’ve carefully surveyed the places rails are joined together, and wonder how steady these reference points will be. I think my surveying is typically accurate to about 4 to 6 mm or so. This railway was an active commuter line from about 1900 to the mid '80s, and for the last few years a tourist train has been slowly traveling them on summer weekends and holidays. Also, this tourist rail service has been replacing the oldest and most rotten ties and doing other minor repair work. There’s a bend of about 30° and two straight sections I care about. Their construction includes wooden ties on a loose stone bed, and separate rails with bolted joints. It looks like many of the bolted joints are also restrained from sliding by spikes driven against their ends or through slots in their sides. Signs of steel moving against the ties generally suggest less than 1/4" of movement.

Thanks!

2

I don’t have any figures for you, sorry, but they do move around. There is, of course, lateral movement on curves, but also “creep” which is forward and backward movement at places like stations where the rails are subject to braking and acceleration forces.

But those are nothing compared to the fact that over the lifetime of a given piece of actual rail (couple of decades maybe), the entire track may be lifted several times, the ballast cleaned and tamped down again, and the track relaid.

Often, if the ballasting is not that great you can see the rails moving visibly up and down by several inches as each bogie of a train passes over. This shouldn’t happen, but it does sometimes.

Rails on the outside of a curve can also tilt outwards slightly as a result of flange pressure. In fact, a key form of derailment as a result of over-speeding on curves isn’t, as you might think, the train toppling over, but rather the outer rail tilting and spreading the gauge, and all the train’s wheels drop into the (now too wide) gap between the rails.

They call it the permanent way, but it’s anything but. Nothing so stable as a bitumen or concrete road.

3

Also, for the reasons I just gave, you’ll probably find the railroad has done a lot of your work for you - look adjacent to the track, and there will be railroad surveying marks of some sort, most likely. I have no idea what form they’ll take in your area, but I’d wager they’ll be there.

4

My father was Supervisor of Maintenance of Way for the RF&P RR. I’ll ask him and see what he has to say. I’ll also see if I can find an old gandy dancer - they’ll certainly know.

5

Under normal climate changes the rails, ties, and all: less than an inch. Hot weather and exposure to direct sunlight the rails can reach temperatures well above 130 deg. F. The rails can move distances of feet or buckle up out of the ground!

If you are doing professional surveying you would know that you should have a stable ‘monument’ referenced to a USGS bench mark from which to work. Rail tracks are not in that category.

If you are an amateur, then in all probablity it makes little if any difference.
With the advent of GPS, why worry?

6

>“creep” which is forward and backward movement at places like stations where the rails are subject to braking and acceleration forces

I wondered - but there’s no stopping in this area, and the trains nowadays appear limited to a diesel locomotive and maybe 2 or 3 coaches, going no more than 30 mph.

>over the lifetime of a given piece of actual rail (couple of decades maybe), the entire track may be lifted several times, the ballast cleaned and tamped down again, and the track relaid

Really? Why do they replace rails? They never seem to look worn out. So, if they did this between-replacement lift & clean, are there any visible signs other than the ballast looking fresh and disturbed? There’s a region that has looked similarly muddy for years, maybe a sign this isn’t happening here. Also, they wouldn’t leave visibly rotten ties in there during this cleanup, would they?

>look adjacent to the track, and there will be railroad surveying marks of some sort, most likely

Ah - I’ve found about 6 places where a length of rail has been set vertically into the ground, sticking out about 2 feet. The top ends appear marked with two chisel blows made at right angles like a “+” or “X”. Sometimes there’ll be a bit of surveyor’s tape tied around them. They are as little as about 30 feet away from the tracks and as far as about 300 feet. All of them appear to have been there many years, though any tape is recent. Is it safe to assume these are surveying monuments set out by the railroad? Any suggestion how I might take advantage of them, other than by using them as my own references and perhaps asking the railroad if they’d share info?

>I’ll ask him … also see if I can find an old gandy dancer

Hey, thanks! That’d be great!

>If you are doing professional surveying

Ah, yes, well, I’m strictly an untrained amateur, no affiliation except with the Historical Society.

>If you are an amateur, then in all probablity it makes little if any difference.
With the advent of GPS, why worry?

Well, the whole thing is just for fun and for the love of some of these amazing old places, with their ruins disappearing under the leaves. But there are various people out there who do love them, and none of them could survey hidden locations in the woods within a few hundred feet, I’d guess. I do use GPS, in fact I have 4 handhelds that do waypoint averaging and under good conditions in an hour or so I can get a position repeatable within a foot or so. But falling water was the stuff of industry before the revolution and as little as 100 years ago, and so many of the niftiest old sites are in creek valleys under heavy foliage and with limited skies, with 50 foot uncertainties in careful lengthy GPS measurements using what I have. With better accuracy, I start being able to pin things down to their shadows in the woods visible on aerial photos. And like I say, it’s all for the love of it. In fact, if somebody were paying for this, and if I had professional equipment, and - ooooh - a rod man or two helping me out and carrying some of the equipment, why, then, I don’t think I’d fart around with rail junctions at all!

7

Why do you want this kind of accuracy? A professional surveyor checking the steel beams for a nuclear reactor would work to millimeter accuracy. But you’re locating old ruins half-buried under mud and leaves.

You’re uncovering history—don’t let unnecessary engineering get in the way of enjoying your hobby.

8

>Why do you want this kind of accuracy?
Well. it’s not so much that I want it, as it is that my situation changed. I had a horrible old transit that had scales 0-90-0-90-0 and verniers that had to be read CW for half the readings and CCW for the other half, and rezeroing the circle was actually much easier than pointing the telescope, and there’s no distancer, and I can barely make out the stadia marks on a pole with this thing, so every distance comes from measuring at least two angles, preferably 3 or more so I can verify I got the right thing. Which, half the time, I didn’t, because the whole setup was so error prone. And the week before they tore down an old bridge that was the most prominent feature in many favorite photos, I measured its position, and had some big disagreement somewhere that’s now unrecoverable. Rrrr. But I recently lucked into a nice digital instrument with a distancer in it, and suddenly my transit measurements are hundreds of times more accurate, perhaps 5 times faster, and perhaps 100 times less likely to have a mistake hidden in them (I mean like a typo or misread scale, not precision limits). The biggest frustrations are gone, and I just remeasured the “backbone” of my main site in about 12 hours, and I am rethinking some strategies to accomodate this excellent fortune.

>don’t let unnecessary engineering get in the way of enjoying your hobby
I hear you. But, I like the engineering part of it. I’m a nerd taking minivacations in the sunshine. I’m not letting unnecessary history get in the way of enjoying my engineering, sort of.

By the way, anybody here know about vertical-axis water wheels or turbines, circa 1900 - 1937?

9

The other place you might get info on the stakes are from the county. The legal descriptions for the land may have those stakes listed in there as part of the easement granted to the RR (or if they own it). That might be able to give you some type of starting point. In addition, you may be able to use those stakes to give you a bearing and distance to other stakes in the area, that you haven’t seen. Some of the stakes they use are big metal rods driven deep into the ground, so they may be hiding out there somewhere.

10

Rails can and do get worn out, as they take a pretty heavy battering. Many railroads will run a rail grinder along every few years. This is to bring the rail head back to its proper slightly convex shape to decrease the rolling resistance of the wheels and therefore improve fuel economy. They can only do this a limited number of times before the rail gets out of spec and needs replacement. Of course, on your local tourist railroad, I’m guessing this probably doesn’t happen - it’s more for high traffic main lines - so the rails there could indeed be very old. You can tell new rails because, counter-intuitively, they tend to be a little rusty. When still new, they are still convex, and you’ll see a thin contact strip down the centre where the wheels have touched, and either side will be a deep orange rust colour. Older rails tend to be shiny right across the rail head as the rail has become flat and the wheels make wide contact. Older, little-used rails will be a dirty brown colour rather than a rusty orange one.

You might find the ballast cleaning guys come out one week, do their thing, and ignore the rotten ties or bad rails, then the tie replacement crew might come out another time, then they might relay some rail another time. Or they might do it all at once. So it’s not uncommon to see rotten ties on new ballast.

Judging by the sound of the line you’re talking about, this stuff might be almost never done. Most tourist railways are low speed, not electrified, and depending on the signalling system, ballast cleaning might not be vital, and what’s a few rotten ties between friends? So the track could remain untouched for a very long time.

I can’t really help you here as overseas practice is probably different to what I’m used to, and I don’t know the first thing about surveying. They might be surveying markers, or they could be distance markers, or right-of-way boundary markers, or a number of other things. I was just pointing out that these markers are probably much more stable than the tracks themselves if you want extreme accuracy.