thanks for the thoughts.
not sure how to measure gauge. posted my thoughts on optical reflection. was thinking of using a pair of axles with n-gauge wheels, close together replacing a single HO axle. one sprung right and the other left and some way (optical alignment ??) sensing too wide/narrow.
which is more critical too tight or too wide?
been thinking about accelerometer and think it may be possible to detect any abrupt rail transition, both vertical and horizontal. large gaps. may also detect concave kinks and maybe misaligned tracks such as track and turnouts. think this is promising if acceleromter is sufficiently sensitive.
hadn't thought about easements. an accelerometer may be able to detect an abrupt change in curvature (i.e. from straight to curve) and may be able to recognize a lack of even minimal easement.
i'm surprised to think that an accelerometer could do so much.
thinking that there could be different cars with different purposes: gauge car, accelerometer car. thinking of 4-wheel bobber caboose frames
greg - Philadelphia & Reading / Reading
gregc i guess it's not obvious that one of the first things that better engineers do is bounce ideas off others, looking for concerns, flaws in their thinking and other ideas that may lead to better ideas. (constructive reviews minimize trial and error) if it's not clear, yes, i'm interested in hearing for others, even the less technical, about what such a car should check for and even crazy ideas for how to do it that could lead to more realizable ideas. don't be shy.
i guess it's not obvious that one of the first things that better engineers do is bounce ideas off others, looking for concerns, flaws in their thinking and other ideas that may lead to better ideas. (constructive reviews minimize trial and error)
if it's not clear, yes, i'm interested in hearing for others, even the less technical, about what such a car should check for and even crazy ideas for how to do it that could lead to more realizable ideas. don't be shy.
I will skip over the issues that you raised in your initial post specific to hand built turnouts.
But here is a list of issues that I have encountered with my own track work, some of which you mentioned in your initial post.
1. Track Gauge. This is one of the most significant causes of derailments and is often difficult to detect with an NMRA gauge. In fact, I don't find an NMRA gauge all that useful because in my opinion it doesn't easily detect parallel rails that are slightly out of gauge. What I would find helpful is a display that shows the spread between rails in decimals.
2. Vertical Rail Transitions. You mentioned "abrupt" transitions which usually result when connecting rails are joined at slightly different heights, but another problem is when the parallel rails are at different heights. How to measure?
3. Horizontal Rail Transitions. You mention abrupt transtions especially on curves. The most extreme example is outright kinks. Again, how to measure?
4. Lack of (Sufficient) Easement Into Curve. There must be an easy way to measure curvature. A simple example is the use of sectonal track. Observe the abruptness of that first piece of curved sectional track adjoining the last piece of straight sectional track. So, when using flex track, how abrupt is that transition from straight to curved?
5. Transition From Track to Turnout. This transition is often abrupt and the result is a severe horizontal rail transition. Once again, how to measure?
Just a few thoughts. Speaking personally, these are my Top 5 causes of derailments on my layouts, past and present.
Rich
Alton Junction
overmod suggested that in the 1st reply
have ordered mpu-6050. need to see how sensitive it is.
wonder if it could sense a horizontal misalignment
Crazy ideas???
An accelerometer connected to an Arduinio?
Seems like the coding would be easy enough to detect flaws....
Ricky W.
HO scale Proto-freelancer.
My Railroad rules:
1: It's my railroad, my rules.
2: It's for having fun and enjoyment.
3: Any objections, consult above rules.
yes i'm interested in building such a car. as I said
gregci'm working on a layout with a lot of hand built turnouts with lots of issues. And would not be surprised if problems develop with use
some have already offered some very worthwhile suggestions
gregc richhotrain Why not try to develop such a car yourself? gregc i'm curious what it would take to design/build a car that can be run over a model railroad to detect flaws in tracks. what do you think i was asking?
richhotrain Why not try to develop such a car yourself?
gregc i'm curious what it would take to design/build a car that can be run over a model railroad to detect flaws in tracks.
what do you think i was asking?
I, for one, would love to see you do it. It would surely beat all of the trial and error testing that we all go through to find the source of derailments on our layouts.
richhotrainWhy not try to develop such a car yourself?
gregci'm curious what it would take to design/build a car that can be run over a model railroad to detect flaws in tracks.
gregc no doubt there will be comments about feasibility or that's there's no need for such a device. i look forward to more constructive comments.
no doubt there will be comments about feasibility or that's there's no need for such a device. i look forward to more constructive comments.
gregc can we put a derailer on this thread before the posts start interfering with the main discussion?
can we put a derailer on this thread before the posts start interfering with the main discussion?
Why not try to develop such a car yourself? If you could accomplish such a feat, members and non-members alike would flock to your side. Seriously!
You mention such gadgets as an accelerometer, optical reflection, and a sensor car with a single truck. Why not take a shot at this yourself?
I've used a coupled pair of the clear plastic cars to aid in identifying flaws in my trackwork. One way to increase the "sensitivity" is to mount a long wire on a low stand in the middle of one car. Extend the wire to about the center of the other car. Any defect in the track will be magnified by the lever arm of the wire. The cars are also very light, so are quite prone to derailing - which in this case is what you want. That won't tell you the problem; that's what the NMRA track gage is for.
-Danial
kasskabooseYou always can buy one:
Hey, that is the one that I have, or one exactly like it..
I did not get mine from Kalmbach. If I am remembering correctly I bought it about 10-12 years ago.
-Kevin
Living the dream.
ndbprr There was one in MR many years ago. It was a clear plastic piece the size of a car with trucks that you could look through from the top to see what exactly was happening.
There was one in MR many years ago. It was a clear plastic piece the size of a car with trucks that you could look through from the top to see what exactly was happening.
appendage angled down contacting the rail that could sense a vertical change. would have a flange to maintain alignment
could something similar sense poor points alignment, a horizontal mis-alignment
how sensitive would it have to be? of course it beeps.
we've all done this kinda thing using our fingers, moving cars across the track, running long locos. i built one of those plexiglass cars. but if there's a lot of track, having something that you can use a loco to push/pull around could help find things that are inconvenient to see. and as I said, i've seen problems set it after some usage.
ndbprrThere was one in MR many years ago. It was a clear plastic piece the size of a car with trucks that you could look through from the top to see what exactly was happening.
I have one, and it proved to be of very little help.
Mine had a six wheel truck on one end and a four wheel truck on the other. It never revealed anything beyond what I already knew by watching "normal" freight cars derail.
A basic NMRA gauge and a straightedge (steel rule) reveal so much more.
A car loaded with sensors might be the best idea, but I cannot imagine it would be affordable or practical to build.
gregc don't rule out some sort of mechanical appendage(s)
don't rule out some sort of mechanical appendage(s)
"...mechanical contact..."
Or are you talking about a "thing" that gets attached to a semi-random car, like a 50' flat?
Ed
For a track geometry car, the only thing I'd really be after is abrupt misalignments. I would base it either on two cars, and their interaction (sort of an A-B car), or a single car with an added truck in the middle. The former would likely be more sensitive. I was thinking two "passenger" cars, painted and detailed to look the part.
An optical system is probably the best way, though that's tech I don't know much about. The other way would be more a mechanical contact system--when it's not adequately aligned, the probe hits its surrounding contact system.
I have spent the occasional few minutes thinking on this, and even have a manila folder for it. I would use it on a Free-mo setup to detect alignment flaws and humps and dips. I was planning on including some kind of alarm system, either aural or visual or both.
For a home layout, where you can just take your time and nobody's looking, you could bypass the electronics and modelmaking, and just have two cars connected together, and a pointer on each one. Shove the car(s) around, and watch the pointer.
I got the idea for this design by watching the couplers move vertically as cars passed over some bad track. It's amazing how bad track has to be before couplers disconnect.
I use a 6-axle diesel and a 2-10-4 steam engine to detect all of the track flaws that you mention.
Of course you could start with John Allen's car, with a BB in a curved track with tilt switches at each end. Intermediate sensors or even a continuous element would add clinometer sensitivity, and an encoder on one axle would give you both position and speed data. Make one crosswise as well as longitudinal and you have curve smoothness and cross-level depending on whether it's stopped or moving...
More seriously, you might adapt the three-axis accelerometer core in a phone to the necessary degree of position. And a camera feed looking at the railhead would give you the 'stripe' from which offset would provide contact patch, and if you are good, perhaps focusably photomicrographically look at the state of corrosion or dirt, microarcing, state of cleaning effectiveness, etc either as a scan or discrete captures. Two properly calibrated, one to a rail, can give absolute and differential gauge.
A problem I see with this is the running precision and lack of play in the moving parts needed to get this to run smoothly. The technology surely exists, but the cost likely becomes the critical factor, with handling the data close behind it.
not sure if "track geometry" is an accurate description. i'm curious what it would take to design/build a car that can be run over a model railroad to detect flaws in tracks.
i'm working on a layout with a lot of hand built turnouts with lots of issues. And would not be surprised if problems develop with use
without worrying about feasibility, what flaws would you want to detect?
here's what come to mind
specific to hand built turnouts
as for feasibility