Lionel PW #41 & #50 Issues

First place I would look within the locomotive would be the armature -specifically cleaning (with a toothpick and CRC 2-26) the spaces between the commutator plates.

While it is apart, cleaning the brush wells (with a cotton swab and CRC 2-26) and checking the brushes and brush springs is advised.

Also not to be overlooked are external factors - a piece of tinsel shorting the track? A worn out circuit breaker in the transformer?

Which transformer?

I have already done all the cleaning and there seem to be no external factors that would account for the shorting. I have been using a transformer that came in a lionel set I purchased new in 2005 or so.  Tonight I took the 41 and 50 to a layout with a PW ZW and another PW transformer and the two little engines worked flawlessly.  Please educate me as to why they worked with the PW transformers but not the newer transformer. Thanks.

You have discovered the potential annoyance of using a modern transformer designed for locomotives with low-current DC can motors and electronics with higher-current vintage AC equipment.

The newer Lionel transformers (e.g. CW40, CW80) are strictly limited in the amount of current (amperage) that they can supply and tend to over-react to the momentary high current draw of the older motors and/or inductive voltage spikes/surges (caused by sparks) by activating built-in "foldback" overload circuitry. The high sensitivity is intended to protect modern electronic components from damage and to prevent catastrophic results from derailment.

Most other modern transformers are far more forgiving to momentary overcurrent scenarios, while the traditional prewar/postwar transformers have absolutely no protection- the breakers protect the transformer, not the train.

In your case, the comparatively more "sparky" 41 and 50 must be operating near the upper limit of the foldback circuit (where any voltage increase pushes it over the limit), whereas the less "sparky" 2349 and 218 are operating farther below the circuit limit. Your observed differences are likely the result of nuances in the physical design of the motor as well as cumulative usage and maintenance over the life of the locomotives. If you have an ammeter/multimeter handy you could possibly see the differences in current draw.

Yeah - go get a used ZW and go make sparks! (Friend of mine found one with original box for $100 recently)

Had a similar problem trying to repair a couple of 1950's milk cars when using a starter set transformer. Worked on them off and on for a week and couldn't get them to work. Ran a lead from the ZW on the layout and bingo. Went to Gene's and got a 1033 for the workbench and all is well.

Bear in mind that the #50 has only a single pickup roller, which makes it more prone to monetary current losses in cases of less than perfect conductivity to the center rail. On postwar transformers that momentary current loss is nearly imperceptible to the eye, but may be very perceptible to modern transformers as noted by Überstationmeister.

The 41 has dual rollers, but is geared much slower than the 50, the 218 or the 2349. This would tend to make any current interruptions that do occur last longer than on the other units as it takes the lower geared unit longer to "roll" past whatever interruption occurs. That may lead to the same result.

I have both the 50 and 41 but do not have any modern transformers to try them out on to see if I can replicate the issue.

Thanks for the replies. The problem seems to be the newer transformer. It wasn't pickups or intermittent power, the transformer would shut it's self off, just like when a wire or derailed car touches the power and ground rail at the same time. I guess the transformer is too sensitive for these more robust PW trains. I'll keep the newer transformers attached to only newer trains going forward. Thanks again.

My meaning is that the momentary power loss is causing the logic in the newer transformer to "think" there is a short and cut off. The sudden rush of current to a postwar motor after it looses power for even an instant can look like a short circuit on a modern loco. The power losses can be so quick that you do not even see it in the operation of the PW loco. Neither the 50 nor the 41 have lights on them so you are not going to see them flash even if there is a dodgy connection. The PW transformer doesn't care and just keeps dishing out the amps and the inertia of the motor caries it over any short interruption. 

Using a PW transformer for them is a sure fire solution, but I think if they are in good repair and the track and pickups are perfectly clean, the newer transformer should work without this issue.

Ashcat posted:

Please educate me as to why they worked with the PW transformers but not the newer transformer. Thanks.

And, of course, was why I asked about your power.

These will probably work fine on a CW-80, but would be a challenge to get running right with a PowerMax(30 watts) or PowerMax Plus(40 watts). While the continuous output ratings of these two are enough for the 41 & 50, the intermittent nature of their power demands will get in to the "foldback" threshold of these little units and they will act erratically. As for using a postwar transformer, for example, either would run just fine on even just a 25 watt 1026/4125.