Older engines on Bachmann track.

[Maverick1]

I have an old 4-6-2 steam engine that still runs great.  However, when it comes to this one switch it stops dead until I move it forward.  It is about 50 years old.  Any ideas.

[ACY]

The obvious thing to do is add tender pick up if it doesn't all ready have it.

[jward]

have you taken it apart and cleaned the comtacts?

when you said it stopped dead you didn't say whether or not is was a dead short. what type of switch does it stop on? is it sharper than the rest? does it stop dead with the drivers on the points? or with them on the frog?

the answers to all of these questions will help pinpoint the actual cause of this locomotive stopping.

[jonathan]

As jward mentioned, without all the symptoms, it's hard to diagnose the problem.  However, here's my experience with older locos.  They tend to be more 'live' than the newer equipment.  Something could be hanging down too low, like a bit of valve gear or a leading truck detail.  This could be touching the diverging track as the loco crosses through the turnout.  Hence, a short.

How old is the turnout?  I have had the stock rail go dead on a turnout.  Again, you wouldn't notice this on a new loco due to all the pick up in the drivers and tender.  On an older loco, where the right side drivers pick up current and the left side tender picks up current, this will also cause the locomotive to stop until you push it past the dead spot.

These two problems have occured on my layout, with running older locomotives.  Fortunately, these are easy to fix problems.

Regards,

Jonathan

[Maverick1]

Well you guys have a lot more knowledge than I do.  But it is brand new bachmann NS track as are all the turnouts.   The engine has a tender.  Also it only happens on this one of 15 turnouts on the layout.  It appears that the engine stops with the drive wheels on the frog and short out the hole layout.  Hope this helps.

[jward]

i am assuming the frame that holds the trailing truck(under the cab)  is metal, as well as the engine body and possibly the tender. i am also going to assume that this particular switch is one of the 18" radius "standard" types. if both of the above are true. then what is probably happening is that the metal frame if the trailing truck has swung far enough to contact either the metal locomotive body or the tender body, often older locomotives were wired with the chassis or body used as a sort of "ground" and thus always the same polarity as one of the rails. if it comes into contact with something which is tied to the opposite rail, like a tender, or possibly a metal truck frame, it causes a dead short. often in older steam locomotives, the locomotive and tender pick up  electricity from opposite rails. usually there is no attempt made to insulate the chassis or metal body from these pickups, thus the locomotive and tender could be opposite polarities. and if they touch on a sharp curve, you have a dead short.

the solution i'd try is to carefully look at the locomotive where it shorts. find out what is in contact with what, and if possible put a small piece of electrical tape on the parts that touch. if they are insulated from each other, your locomotive should work fine. if you can't do this, consider replacing that switch with something with a gentler curve like a #5 pr #6 switch. or just don't run that particular locomotive through the curved route of that particular switch.

[Jim Banner]

Fifty years ago, it was common for the locomotive to pick up from the right hand rail and the tender to pick up from the left hand rail.  If both the tender and locomotive were metal, their bodies would usually have opposite polarities.  So if the draw bar was too short and the bodies touched on a bend in the track, the resulting short circuit would shut down the layout.  Most of this type of locomotive had a wire from the tender to the locomotive but sometimes they used the draw bar to transfer the current.  In the latter case, you could also have a draw bar short, either from an inadequately insulated draw bar pin or from the draw bar touching the body on rough trackwork.  This was a problem that today's plastic locomotives do not have.  But with your old locomotive, it is something to keep in mind.  It is also a very good reason to not go blindly ahead installing tender pickups.

Jim

[rogertra]

Yes, engine picks up power on one side, tender on the other. Tender contacts engine cab?  Short circuit!

Good observation Jim.  :-)

[Maverick1]

So I took everyones advice and spent Saturday morning taping up possible contact points.  I also watched the engine run over the turnout.  Here is what I saw.  As the engine passes over the turnout it stops when the lead drive wheel passes over the plastic frog (?) and touches the metal rail.  At that time the second drive wheel is still touching the metal rail on the other side of the plastic frog.  I can move the engine forward a quarter of an inch and it runs fine.  Now this is on one of my mainlines and the engine passes over 5 other turnouts with no problem.  Also it stops when going straight.  When I ran it on the curve part of the turnout there was no problem.  Also when it stops it shorts out the whole system.  Any ideas? 

[J3a-614]

Here is another possibility, although I don't know if it applies to your switches:

Some switches, among them Atlas types, are live all around with appropriate polarities.  This includes in the frog area, where rails of opposite polarity are in close proximity.  Short circuits are prevented in the frog area with a point that is either insulated from the adjacent rails, or may be of an insulating material in itself, such as plastic.  This is a typical "dead frog," and its inability to carry current is not normally a problem if the locomotive in question is long enough to bridge it.

However, two rails of opposite polarity are quite close together at the point of such a  frog, with a relatively thin insulated section between them.  It is possible for some wheel treads to bridge this insulated gap, causing a short circuit there.  If this is the problem, a touch of a tough insulating coating over these closely spaced rails can make the switch usable.  Classically, nail polish was used for such work.  Of course, it can wear eventually, and you also have a longer dead frog as a result as well.

One thing you might want to do that hasn't been mentioned here is to run this locomotive over the track in question in the dark.  There is a pretty good chance there will be a spark of some sort at the location of the short when it occurs; watching for it in the dark will make it easier to see.

[Jerrys HO]

Mav1

Well you guys have a lot more knowledge than I do.  But it is brand new bachmann NS track as are all the turnouts.   The engine has a tender.  Also it only happens on this one of 15 turnouts on the layout.  It appears that the engine stops with the drive wheels on the frog and short out the hole layout.  Hope this helps.

My suggestion is if it's only that one turnout, call the service dept. and send it back for a replacement.

Jerry

[jward]

the one thing we haven't been told is what makes this particular switch different from all the others. is it a different size? we now know that the locomotive does this while going through the straight route, not the curve. this i find rather odd in itself. the use of clear nail polish is a good start, but i'd be careful with it on plastic parts. make sure it doesn't affect the plastic before you apply it to a critical area like a frog. try a little nail polish on one of the ties, which should be the same plastic as the frog.

[Maverick1]

thanks guys I,ll give it a try.