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+---- Thread: WOOHOO! Good weather = time to build (/showthread.php?tid=2117)
Re: WOOHOO! Good weather = time to build - Gary S - 07-11-2010
You're right Kevin, not only does running the trains find flaws in the planning, but it also finds flaws in the trackwork. So far I am okay though, no problems on the mechanical aspects. I did have one boxcar that derailed at the same switch every lap. Every other car and loco went through the switch perfectly. But the one boxcar was amazingly consistent, it derailed every time, but only on that one switch! It wen through all the others just fine. I wonder what little intricate detail is wrong on that bocxcar that made it derail there. I did notice that the car was not quite as free-rolling as the rest. I'll check it out tomorrow, probably put new wheels on it and see if it changes anything.
Re: WOOHOO! Good weather = time to build - nachoman - 07-11-2010
Gary S Wrote:You're right Kevin, not only does running the trains find flaws in the planning, but it also finds flaws in the trackwork. So far I am okay though, no problems on the mechanical aspects. I did have one boxcar that derailed at the same switch every lap. Every other car and loco went through the switch perfectly. But the one boxcar was amazingly consistent, it derailed every time, but only on that one switch! It wen through all the others just fine. I wonder what little intricate detail is wrong on that bocxcar that made it derail there. I did notice that the car was not quite as free-rolling as the rest. I'll check it out tomorrow, probably put new wheels on it and see if it changes anything.
betcha it is out of gauge
Re: WOOHOO! Good weather = time to build - Gary S - 07-11-2010
I'm heading out there with my NMRA gauge right now. But why doesn't it derail on the other turn-outs?
Re: WOOHOO! Good weather = time to build - faraway - 07-11-2010
Gary S Wrote:I'm heading out there with my NMRA gauge right now. But why doesn't it derail on the other turn-outs?
It's sometimes bad luck if a wheel set that is at the very min/max side meets a turnout that is at the opposite min/max side. In that case the NMRA gauge may fail because both components are marginal within the specs. I use my digital caliper in such cases.
Re: WOOHOO! Good weather = time to build - nachoman - 07-11-2010
faraway Wrote:It's sometimes bad luck if a wheel set that is at the very min/max side meets a turnout that is at the opposite min/max side. In that case the NMRA gauge may fail because both components are marginal within the specs. I use my digital caliper in such cases.
That is usually what I find. Most of the cars make it through fine, but one wheelset is a little out of gauge. The reason it doesn't derail at all the turnouts is because that one particular turnout is also a little out of gauge. You may have one wheelset *slighty* wide and one turnout *slightly* narrow. All wheelsets that are exactly in spec will make it though the turnout okay, but the one wheelset that is just a tad wide will have problems.
Re: WOOHOO! Good weather = time to build - doctorwayne - 07-11-2010
Another possibility is that all of the wheels are in-gauge, but not aligned at the same points on their respective axles, causing the truck to run skewed.
Wayne
Re: WOOHOO! Good weather = time to build - scubadude - 07-11-2010
Sounds to me like you have the makin's for a nice converted boxcar storage facility for one of your interchange yards
Re: WOOHOO! We've got "Tolerance Build-up" ... or "Shrinkag - P5se Camelback - 07-11-2010
Here's where we have a situation commonly known as "tolerance build up" - when each dimension in a succession of dimensions is within the plus-or-minus tolerance, but maybe in this case all are on the "plus" end of the tolerance scale. Now we introduce a part that is on the "minus" end of the tolerance scale, that fits into a hole at the far end of that succession of dimensions, all which we know are within tolerance. But even though all parts are within tolerance ... horrors ... the new part doesn't fit!
The solution to that particular pitfall in part design is a practice know as "datum dimensioning," or "dimensional tolerancing," where all subsequent dimensions after the initial one are measured from a "zero datum" or initial measuring point. This system eliminates the potential for "tolerance build-up." Of course, the same scenario could also present itself in the opposite tolerancing direction, in which case it would be "Tolerance Shrinkage," but the result would be the same ... a part that doesn't fit and a production tool that has instantly become a piece of very expensive tool steel junk!
I hope everyone was paying attention and that those with weak memories were taking notes, as there will be a quiz at the next class meeting!
Edit: The class instructor cleaned up syntax, grammar and spelling errors. Grading of the referenced test will be lenient due to the aforementioned errors in lesson delivery.
Re: WOOHOO! Good weather = time to build - mountaingoatgreg - 07-11-2010
And I thougth "shrinkage" was what occured when you got into really cold water...
glad I was able to learn something
I hope you find a quick and inexspensive repair to you problem and you can get back to testing the layout.
Re: WOOHOO! Good weather = time to build - Gary S - 07-11-2010
I haven't taken the time to determine the problem with the boxcar yet - I did get the spurs in Industrual Area 3 done though. Permanent magnets, feeders, and track laid. I also installed the last two turn-outs at Middle Yard. All that is left there is to extend the RIP track and another spur.
Thanks for all the thoughts on the boxcar issue. Great comments on the "one at that end of spec and the other at the other end of the spec" possibility. I did check the wheelsets with an NMRA gauge and they were dead on. As I mentioned earlier, this particular boxcar was "sluggish" when rolled on the track. When the other cars are rolled by hand, they travel a good distance down the track, but this car didn't. I'm thinking that had something to do with it.
scubadude Wrote:Sounds to me like you have the makin's for a nice converted boxcar storage facility for one of your interchange yards
Worst case, I'll change the trucks and wheelsets. I did replace the wheelsets today, but didn't take the time to run it through the switch. Maybe tomorrow.
biL Wrote:Here's where we have a situation commonly known as "tolerance build up" - when each dimension in a succession of dimensions is within the plus-or-minus tolerance, but maybe in this case all are on the "plus" end of the tolerance scale. Now we introduce a part the fits at the far end of that succession of dimensions, all which we know are within tolerance, that is on the "minus" end of the tolerance scale, but still within tolerance and ... horrors ... it doesn't fit!
I've always found a big hammer to be the solution...
Re: WOOHOO! Good weather = time to build - Russ Bellinis - 07-12-2010
Gary, do you have one of these tools? <!-- m --><a class="postlink" href="http://www.micromark.com/HO-TRUCK-TUNER,8241.html">http://www.micromark.com/HO-TRUCK-TUNER,8241.html</a><!-- m --> If you don't have one, get it! It is the best way that I know of to make poorly performing trucks into free rolling trucks!
The other thing that may affect it is tuning the trucks to the freight car. The "three point" suspension system for freight cars has been "gospel" forever in model railroading. I was at a model railroad gathering recently where the focus was on clinics all day, rather than operating layouts. One of the clinics was given by a member of a local model railroad club where they used to have problems with rolling stock derailing regularly because the track was not absolutely perfect. They came up with a solution to the problem that did not require the club to rip up their layout and relay all of the track!
What he discovered is that mass and weight does not scale well. Therefore a suspension system that works for a prototype weighing thousands of lbs doesn't work reliably for a model weighing a few ounces. IN case anyone is not familiar with the three point suspension system, it consist of having one truck on a car set just tight enough that it will rotate freely, but not rock. The other truck should rotate but also rock slightly. What he discovered was that if a truck will not rock on a model, if there is any place that the track is less than absolutely perfect, the wheels on that truck would lift off and the car or locomotive would frequently derail. His solution is to place a locomotive or car on the tracks and using one finger, tip the top of the car 1 scale foot ( in ho scale @1/8 inch). If the wheels on either truck lift, that truck is too tight. If you can tilt the car significantly more than one scale foot without the wheels lifting, the trucks are too loose. I haven't tried it, but there were a number of guys from that club there who said that setting up the rolling stock in that way made a huge difference to the point that when newbys joined the club they frequently had derailment problems with their trains. Once the rolling stock was set up this way, derailments became a thing of the past if nothing was bumped and no earthquakes occured.
Re: WOOHOO! Good weather = time to build - Gary S - 07-12-2010
Interesting points on the "three point" adjustment. I always did that without giving it much thought - after all, the experts said so! I'll give it a try. Thank you Russ.
Now, about that particular car, the new wheelsets I put on solved the problem.
Layout Progress Report: More wiring completed this evening, then I cleaned the track, installed the removable bridge, and got 4 trains rolling around the loop, and sat back and watched. Very very cool! And it is getting me primed to do some scenery - it is still a bit away, but when the time comes, I'll start carving all the ditches and low areas into the foam, and work on the areas where the bridges will be. Then some brown paint on the foam and it will start looking like a layout.
On a DCC note, sometimes it can baffle me. I was playing around the other day with a couple of the CF7s. So tonight, I put them on the track and they take off all by themselves, at around 75 percent throttle. On the utility throttle, I select the loco number for one of them, and nothing. The loco continues at speed. So I try address 03. Still nothing. Same thing with the other CF7. And then I try to gain control with the DT400, but nothing I do gains control of the locos, they just happily circle the track at 75 percent speed. It is my belief that on occasion, random cosmic rays strike the memory and the loco forgets who it is.
This has happened before, no big deal, just reprogram the address and all is well.
Re: WOOHOO! Good weather = time to build - Steamtrains - 07-13-2010
Hi Gary....What DCC system are you using..?? Something similar happens to me (Digitrax Zephyr). After an operating session I'll shut down. Next time I turn things back on a couple of the locos used previously will crawl on their own, even if their assigned throttles are at zero, or even turned off. The fix (sometimes) is to re-select the loco on an active throttle and start it up a bit. Then stop it and "dispatch" the loco address from the system. If this doesn't work, I'll shut the whole system down, wait a few seconds, and turn it on again.....
A couple of weeks back I got a "short" error shortly after turning on the system, and I couldn't figure out what was going on. Turned out a loco had crawled its way to a turnout that was set against it.....
Re: WOOHOO! Good weather = time to build - nachoman - 07-13-2010
Methinks the problem is likely the decoder. I assume they have a tiny memory chip in them to store their address and CV settings. With any type of electronic memory, there is a chance of corrupting the memory by static electric discharge, radiation, or heat. Since they aren't grounded to an earth ground - I think the chance is reasonable that a large electrical storm could corrupt their memory.
Re: WOOHOO! Good weather = time to build - Gary S - 07-13-2010
Gus, I have the Digitrax Empire Builder. I've also noticed that with the utility throttle, and the loco stopped, if I turn off the system and then turn it back on, the loco will start moving at a slow speed. Simply speeding the loco up and then stopping it reverts back to normal.
Kevin, the foam on the layout can be kind of "staticky" on occasion. Wonder if that may play a part.