Need help fine tuning the Hogwarts Model--Photos Added.

[BR60103]

Chip: we had an operting session a few months ago with 3 Bachman Hogwartses in attendance. One fellow was doubleheading his paie, and one of them had a real tick in the mechanism. We think it was too much play in the drivers. A young fellow brought his and it wasn't running at all. When I left, the layout owner was working on it.
My own loco seems to be operating OK.

[SpaceMouse]

I put the new screw in and now it is really bad. How bad? If I move the engine ahead 1/4 inch, the left front wheel of the truch pops off the track. I tried a washer, Same thing.

The drivers are not involved at this point.

[rrinker]

Something is bent or too tight. I used to have one of those Tyco 4-6-0's, of all things the Bicentennial one. The front truck would NEVER stay on the track no matter what. I ended up pulling the screw up tight which raised the wheels off the rails. Steam engines are a fickle lot. I would start by doing what was suggested and removing the boiler and motor so you can pu***he chassis around and attempt to observe where the problem is coming from. It should move easily - if there's a hitch in it, the rods are not correct or the quartering is off. If it won't roll smoothly without the motor, it won't run smoothly with it.

--Randy

[SpaceMouse]

Okay. For laughs and giggles I took the front truck completely off and ran it around the track. It ran smoothly with no derails including both high and low speeds through the S turns.

I put the front truck back on and finally noticed something that has been staring me in the face. The rear wheels of the front truck are squarely on the track. The front wheels are light and up a little like a perpetual wheelie. Move a quarter inch and they jump ship.

So how do I even out the load. I'm thinking a shim under a washer under the spring to force the front end down.

[Anonymous]

The front end of the truck is lifting for a reason - something must be either bent or jamming against something else. I would check that it's not jammed against the chassis anywhere and that the mounting isn't bent - I had an N scale 2-6-2 which wouldn't pull anything and ran badly, traced it to the lead and trailing truck mounting arms being bent. Bear in mind that you want just enough weight on the truck to keep it on the rails - any more (or too stiff a spring) and it'll lift the lead drivers off the rails. Hope this helps!

PS. Regarding the original "Hogwarts" - in my experience the main problems with Bachmann OO steamer mechanisms are with wheel quartering (seldom correct from the factory - I've seen a few brand new examples tested and been appalled, the one I have took about 6 months tweaking to get running properly), and also out-of-gauge wheelsets. Set both of these correctly and run for an hour's break-in in both directions, and you should have a smooth-running loco. Hoping this might be of use to anyone trying to fix one of these!

[SpaceMouse]

I agree that there is something wrong with the front end. But I have yet to determine what it could be. As as the truck is sitting on the track, not only does the front end sit higher, it seriously wants to pu***o the left. The only thing that determines it's location relative to the chassis is a single screw within a brass sleeve that determines the height. I just replaced the screw so it is straight. The wheels can hit the sides of the chassis with extreme turning, but that fare exceeds the turn of an 18" radius. Ultimately, what holds the truck in place is the brass sleeve which is maybe 1/32 in thickness around a 1/8 inch screw, and the screw head which might be 3/16 in diameter. Theoretically, the spring then is placing torsional stress on the truck and would be the only thing altering its position relative to the chassis--well that and gravity of the truck and the gravity of the metal boiler.

Any other ideas or theories?

It could be the weight of the boiler pusing down on the truck that is causing the front end to rise. If this is the case, the front end needs to ride higher relative to the chassis.

[davekelly]

Space,

Is it possible to post a few pics of the truck in question as well as the method used to mount the thing on the engine? While you are doing a great job of describing it, it is still somewhat difficult to picture it in my mind.

[SpaceMouse]

I can, but it will be late tonight as I rush from work directly to my train club meeting. I'll get home around 11.

[Anonymous]

Chip
Have you sat the front truck by itself on the track and rolled it? I wonder if the truck is bent, or out of gauge or could it be backward? Something sounds out of alignment for sure.
Photos will help. Can you take a couple of just the truck, top view and side view?

[SpaceMouse]

The only thing missing is the spring that rides between the chassis and the truck. I didn't know how to make one.

[Anonymous]

Might check the phone book for a local spring manufacture. Sometimes they well have left over springs from previous jobs, that might work.

Just a thought....

[davekelly]

I think Gary is on the right track. Looking at the way the truck is mounted, it seems that the front end would ride up if the truck frame is bent. I agree that it would be beneficial to set the truck by itself on the track. The next thing I would try is to mount the truck without the spring to see if it sits right. That way you can tell if the mounting screw is square with everything else - it may be set at something other than 90 degrees which would cause the truck not to sit level.

[SpaceMouse]

I see your point.

AS I stare at the diagram, to me what seems logical, since I just replaced the screw. that the truck is warped or possibly the screw was tapped out of square, like you and Gary are suggesting.

[Anonymous]

QUOTE: Originally posted by davekelly

I think Gary is on the right track.

Nice pun dave. [swg]

[DigitalGriffin]

Could one of the wheelsets be out of gauge causing it to ride up the rail? I dunno, I'm just guessing.

[Anonymous]

NOOOOOO!!!!
]
I just finished painting my MDC 4-6-0. Ran it around today, runs great, but then i noticed.... I forgot to put the pilot truck back on. So i got the pilot truck and the sleeve to put it on, but lo and behold, no spring!!! For now i am stuck running with no pilot, if you find a source for that spring please tip me off! My model is identical to yours so whatever spring you get is what i need.


Thanks in advance[8D]

[SpaceMouse]

Sorry, I'm not missing the spring I just didn't want to figure out how to draw one in the program.

[Anonymous]

oh, well, my search begins.....

[Don Gibson]

MOUSE

Your Pilot truck's float and are not totaly making the curve, because:

Rigidly coupled drivers are pivoting one way, while the pilot trucks are trying to follow the rails. CLUE: The pilot truck's track when not attached to the body.
The body 's lateral angle is too great for the pilot truck to follow .

Get rid of your problem causing 'S' curve by either straightening out, or inserting a piece of straight .


(signed) Grumpy Don

[West Coast S]

I duuno if this is worth a grain of salt for your problem. Replace the plastic pilot wheel with a quality one from Northwest Shortline. I had to do this with Every MDC, besides better appearence my experience is they maintain proper guage and track better.

[Anonymous]

WHAT LUCK!

Walking around in my train room barefoot paid off! I stepped on something so i picked it up, turns out it was my pilot spring completely undamaged. YAY![:D]

[selector]

I agree with CNJ831. You can't make a silk purse out of a sow's ear...as me dear ol' mither used to say.

Mouse, your first priority, if I have any sense of your circumstances, is to get your child to enjoy the trains. That's #1. Number 2 is that YOU are not enjoying this part of it. So, how will your autistic child enjoy it if you can't? Now, let's see how the missus is viewing all of this, because she, too, is very much in the equation....probably somewhat dimly, right? She's not too thrilled?

If I hear you, and read you correctly, you have no practical choice but to move on. I know that money doesn't grow on trees, so maybe you will have to defer the rest of the layout for a couple of months, or so. It happens, Dude. Go the sane way, get a replacement, and move on. Besides, you'll have time for a second look at your plan. You may surprise yourself by seeing some needed changes. That, too, happens.

Good luck, and don't despair. Another thing me mither said was, "All good things come to he who waits."

Best regards.

-Crandell

[Don Gibson]

CRANDELL:
You make too much sense. Your mater must have been one smart 'mither', too..

[Anonymous]

Regarding this pilot truck problem... Make sure the wheels are in gauge and mounted squarely on the axle (and it sure wouldn't hurt to replace the plastic pilot truck wheels with Northwest Shortline wheels).

Make sure all the parts are assembled in the correct direction. The spring is shaped like a cone and the wide end should sit inside a ring molded into the truck. The truck mounting slot is a slight arc which means there is a front and back side to the truck assembly - the arc should "point" towards the front of the locomotive. Replacing the MDC parts should be unnecessary unless they've been damaged.

If the truck mounting screw is not square with the locomotive frame, the screw could put unwanted stress on the truck. Adding washers between the truck and spring is likely to be a source of trouble as this would not only prevent the spring from sitting inside ring, but could also introduce strange forces.

The weight of the locomotive has no effect on the front truck (adding weight will only increase pressure on the drivers). Adding weight to the front and rear of the truck (i.e. above the axles) might help but should be unnecessary. BTW, a properly weighted model locomotive will balance between the front and rear drivers.

The following is unrelated to the pilot truck problem... The MDC 4-6-0 has a fairly long rigid wheel base (distance between front and rear drivers). Blind center drivers or narrowing the gauge of the drivers by 2-3 thousandths of an inch might help this locomotive run on sharper (less than 24 inch radius) curves.

[selector]

Dave, I second that excellent post. I fooled around with my BLI 4-6-4 because I thought it squatted a tiny bit over the rear truck. It looked like the cab roof was not high enough compared to the tender next to it. So, I tried putting a ball-point pen spring under the rear truck, and, depsite eventually cutting the spring until only 1/3 of it was left, it still lifted the rear drivers off the rails. Needless to say, I went back to the original plan that the designers had all along. (sigh) Bottom line- it didn't work until I put the old spring back in.

[howmus]

QUOTE: Originally posted by howmus

Chip,

It sounds like the front truck is binding somewhere. It may be that in the S curve, the engine is pointing one way while the truck is going in the other and the truck hits the side of the frame.

QUOTE: Originally posted by Don Gibson

MOUSE

Your Pilot truck's float and are not totaly making the curve, because:

Rigidly coupled drivers are pivoting one way, while the pilot trucks are trying to follow the rails. CLUE: The pilot truck's track when not attached to the body.
The body 's lateral angle is too great for the pilot truck to follow .

Get rid of your problem causing 'S' curve by either straightening out, or inserting a piece of straight .

In other words you think the problem is what I said the problem might be two pages ago??? LOL I love it when the experts like yourself agree with me (and I do consider you to be one of thee experts). Makes me feel like I actually know some things. [:D]

[SpaceMouse]

The S curves are turnouts back to back and cannot be replaced without totally starting over and I'm not going to do that until build my basement layout in a couple months. I will tell you this, I've worked those turnouts until every other engine in the stable makes through without derailing--ever. The 4-6-0 makes it through these S turns at speed with the front truck removed.

The issue right now is not that it doesn't make it through an S curve, its that it doesn't make it a quarter inch on the straight.

Now I may give up on this 4-6-0 some time in the future, but until I find that the problem is unsolvable--like it is an known design flaw of later model MDC 4-6-0s, I'm going to work on it. Those of you that are giving up for me, you may yet prove right, but there is still a lot of things to try before I reach that point.

[Roadtrp]

I hate to admit it, but at times our wives are right. [;)]

I had one locomotive that was making me absolutely crazy. I stayed up until 2:00 AM a couple of nights trying to get it to run properly, and went to work dead tired the next day. One night I stayed up until 4:00 AM messing with it and called in sick the next day -- there was no way I could work.

My wife asked me how many hours of work it would take me to replace that locomotive. I said two hours... maybe three hours after taxes. She nicely asked me if I was totally out of my freaking mind for spending as much time on it as I did. I had to admit she was probably right.

I dumped the locomotive in the garbage can and bought a replacement. The replacement ran perfectly right out of the box. I have come to the conclusion that the occasional piece of lousy equipment is just something you have to deal with in MR. You can let it make you nuts or just replace it. In the long run, the money spent replacing it far less costly than the sanity lost in trying to fix the lemons.

[dave9999]

Chip,
I have to admire your determination, but Roadtrp has a point. It's seems to
me that you are spending a lot of time and effort, not to mention the grey hair
that you are obvious getting, on one locomotive. Put it a side for a while. Work
on something else, And some time in the future, if you feel it's still worth the
effort (headache), give it another shot.

Remember, The best way to suck the fun out of a hobby is to turn it into work.
Good luck, Dave

[SpaceMouse]

I appreciate your point of view. However, my wife's job just came to an end and until we replace that income, I doubt an new engine is in the works.

Now back to the problem.

Here are the pictures I promised. Sorry about the truck close-ups. It did not seem tweeked and road the rails well without much slop.



This photo best illustrates the problem. Notice that when the engine is at rest the front wheel of the truck is about 3/64ths higher than the back truck which is firmly on the rail. The flanges just barely grab the inside of th rail. As soon as it moves, it pops out.