Hi all,
I'm a little of a forum lurker at the moment and am slowly piecing together layout ideas. This said, I have the baseboards ready to go, so I am now up to placing track conceptually. The track is all hornby.
Also, I have previously been working with Hornby traction and rolling stock(OO), using their tension lock couplers. This week, I have made the move towards more realistic traction and rolling stock(HO), using kadee style couplers. I have purchased a Kato AC4400CW loco and a single atlas gatx 20,700 gallon tank car.
I have upgraded one end of each to kadee #5 couplers, leaving the opposite end with the OEM couplers.
I am finding that now, the tank car is being derailed when the unit crosses a turnout to a parallel siding. this happens as the locomotive is becoming parallel to the main track, as the tank car is negotiating the turnout. My first (and only) thought is that the couplers are placing pressure on the tank wagon (lighter of the two) and 'flicking' it off the rails. I have tried the various combinations I can with the different couplers; ie. kadee + kadee, kadee + OEM, OEM + OEM.
Track layout in this area is a single left turnout, followed immediately by a right right curve to make parallel siding.
Your help is appreciated,
Cheers,
Brett
The Railroad must get through . . . . .
http://blandfordrail.wordpress.com/
If you watch very closely you may see that the trip pin on the coupler is hanging up on the turnout at some point and causing the tank car to derail. bending the trip pin up slightly or simply snipping it off will stop this from happening.
Dr. Frankendiesel aka Scott Running BearSpace Mouse for president!15 year veteran fire fighterCollector of Apple //e'sRunning Bear EnterprisesHistory Channel Club life member.beatus homo qui invenit sapientiam
It is almost certain to hang up at the frog. Trip pins also hang up at crossings.
Hi Brett,
My first suspicion is that the trip wire is hanging too low and it's hitting one of the rails in the turnout. Does the car derail if you push it through the turnout manually? It might be a good idea to check your coupler height with an NMRA or Kadee gauge. If it's the wire, a careful adjustment with pliers will likely fix it.
Phil, I'm not a rocket scientist; they are my students.
Push the car through the switch manually. If the coupler is hitting the frog, you will see it move. If it does not move, that's not the problem.
The way I interpreted your initial post, it's not a heightproblem. Instead, you seem to think that the loco coupler is pushing the light tank car off the track. This is certainly a possibility. It is caused by two things: the radius of the track is too small and the couplers do not have enough side to side motion. This is the reason many manufacturers mount couplers to the truck to go around tight curves.
If this is the case you need to see if you can make your couplers swing more and add weight to the tank car. I usually fill them partially with sand. If this does not solve the problem you will need to consider larger radius curves and switches. By the way, what # switch are you using?
Check out the Deming Sub by clicking on the pics:
Another thing. Do you have an 'S' curve. Meaning that the track curves to the right and then immediately to the left? This can also cause lighter cars to derail. To alleviate this you need to add a straight track in between the curves. Adding weight will help too. Hope this helps.
Check if the coupler trip pin of the tank car is hitting the footboard/snow plow of the loco.
COUPLERS are what what connect cars. They swing in arcs.
Since they connect (pull and push) cars, their geometry imposes limits as well as the track radius through curves.The 'laws of pysics comes into play -, both for the prototype and our imitative effortts.
For the record,EVERYTHING has some limitation. (So do WE).We 'Modelers' want realism. detail, and function,, on UN-realistic curves. Basement layouts have unyielding walls - as do Garages, and Spare rooms.
WHETHER you agree with it or no 22"is an accepted standard, and being approached,.by 18"r. WHY?, because of the economics of the 4X8 plywood board,(which is fine for 'N' gauge)..
RE KADEES:.(using #46 instead of #5's). Since car's wheels & Pivoting are a couple of inche inboard from the ends, A longer coupler helps.
.
1. CHECK couplr height.. 2,Wheel gauge. 3. Hornby Flangeways 4.Vertical/Horizontal Truck Play
First before doing anything check the trip pin height by using a KD coupler height gauge..Then if need be check the wheel gauge and then check the switch by using a NMRA gauge and by pushing a car slowly through the switch watching the trucks.
Larry
Conductor.
Summerset Ry.
"Stay Alert, Don't get hurt Safety First!"
Thanks for all the feedback.
Firstly, I have now checked the trip wire, and it appears the coupler on the tank car touches rail at the crossing - recitified.
Next, the coupler heights are slightly different on the loco Vs. rolling stock - shopping list to include Kadee height gauge.
Turnout has an effective radius of 18inch, which is joined to another 18inch radius curve in an 's' formation. I will play with this tomorrow to see if I can make a difference by placing a straight section in the middle. Would the major rectification here be to move to a point/turnout with an effective radius of 22inches, joined to a curve of 22inch in an 's' formation? I am trying to maintain parallel and consistent (over the whole layout) track centres, which I think this may do.
Looking closely at the 'flicking' action, as the couplers are mounted to the vehicles, not the trucks, the formation of the 's' curve is causing considerable sideways travel in the couplers. I will also place #46 Kadees on the list of things to buy to check if this rectifies the problem. A longer coupler (6/64inch) may give enough freedom to make this turn.
Again, thanks
Brett.
That is an awful big engine to run through 18" radius turns. The engine might go through, but there is enough overhang to flick the cars right off. Smaller engines are needed for 18" turns. An early SD or most any 4-axle engine will handle the turns much better. In real life there are many places where 6-axle power is not supposed to tread, due to curvature.
Mike WSOR engineer | HO scale since 1988 | Visit our club www.WCGandyDancers.com
A turnout in 18" radius (#4) is a very sharp turn for a large loco. A #5 or #6 would be better.
jeffrey-wimberly A turnout in 18" radius (#4) is a very sharp turn for a large loco. A #5 or #6 would be better.
Actually it depends on what #4 switch you use. A Custom Line #4 switch makes a nice small crossover which which has a smooth diverging route.
A Custom Line Mark 3 #4 can be use as well as a crossover on slow speed ISLs.
http://www.firsthobby.com/store1/Product.asp?ProductID=ATL282&SN=2008110609232109
However,this jewel can be used in tight situations where slow speed switching is involved but,never has a high speed main line crossover.
http://www.firsthobby.com/store1/Product.asp?ProductID=ATL850&SN=2008110609232109
Of course in using these smaller switches common sense must rule when choosing locomotives and cars.A SD70 can go through a Custom Line #4 at resticted speed..
Chances are, the things you've already done will solve your problen, but you should know about this one other thing because it may help when it seems like there is nothing left to fix.
Sometimes the wheels on a truck are in gauge, but off center. When this happens it can make a car very prone to derailments on anything with a frog or points (crossings and turnouts) - especially if both axles have off center wheels, but in opposite directions.
I've tried to illustrate it for you:
Notice that the wheels are in gauge on the axles, but the wheels on the upper axle are off center to the left and the other axle is off center to the right. Such a situation makes the car perform very unreliably, but it's usually pretty easy to center and re-guage the wheels - it's really a matter of knowing to look for this as a problem.
Good luck.
Veerrrryyy nice diagramme, Phil!!
If you discover you have a dog-leg truck like that described above carefully realign the wheels on the axle and check them with the NMRA gauge. Once you're satisfied they're in gauge apply a small drop of super glue at the axle on the backside of the wheel. Or you could go the easier route of replacing the wheelset.
Brett;
Your Subject question above (Tournout derailments) is too General, and the answer is "Sometimes"
IF iit is confined to a single product your ahead of the game (you know where to look.)
DERAILMENTS are cause by wheels not following track. WHY is the $64 question.& in your case, a Kadee #205 coupler height gauge is a prerequisite. It.establishes a STANDARD.to follow..
ONE is 'trip pins..If too low they snag. TWO there are 2 causes: ('DROOP and coupler pocket HEIGHT). Each has a different cure.- (trim or raise).
THERE ARE others.. Only your Eyeball can find.
An update on the progress here :-
I have purchased #205 coupler height gauge, and have found that all couplers are very close to the correct height (as described in the Kadee instructions).
Trip pins clear the track while traversing the turnout, frog etc, while each vehicle is moved slowly over the turnout.
All other parts of the layout are traversed fine.
I have sourced #6 turnouts (852mm radius) and appropriate curve to create parallel siding. I will test fit this to the layout tomorrow to see if the reduction in turnout radius has helped rectify the problem.
Also, I should have a packet of #46 Kadees tomorrow.
Again, thanks for all your assistance, and I'll give an update tomorrow.
I'm having the same problem. Could the turnout be the problem? I am using Atlas snap switches and I'm getting derailments when traveling into the turnout, that is to say, from one of the arms to the stem. Should I invest in higher quality turnouts?
Update, the 852mm radius turnouts and s'curve to parallel siding have solved the problem.
On laying some more track, and testing with this large loco, the 18inch radius curves represent the same problem when using the Kadee #5's, but not the OEM knuckle couplers. I am still sourcing the #46 Kadee's, as the shanks on the OEM couplers appear to be a little longer than the number 5's.
Again, thanks all.