Hi Everyone, I'll try and keep this short, about a short. I have 4 (four) Athearn Geeps all set in a consist. Two came motorized, and I added motors to the other two that were previously dummy units. I'll refer to the two dummy units as 3 and 4. 3 runs fine both by itself and also with the other two motorized units, forward and reverse. 4 runs fine by itself and with one or two other motorized units, but when I lash them all together, 4 sometimes reads a short on my throttle (DCS-50) and stops them all from running. In a moment or two, 4 may start back up again. I can run the first three units just fine, in both forward and reverse, just not with 4 added on the end. Question: why does my 4th locomotive want to occasionally short out when lashed to the other 3 units but not by itself? I use DCC and all decoders seem to be working fine and are completly isolated. I am attending a show next month with my modular club and would really like to run all 4 engines together in a consist. Your thoughts or suggestions are very welcome.
Thanks
JRP
Are your couplers insulated from the frames? The couplers could be shorting out depending on how they move.
Easy to tell - when you put all 4 of them togethr and it shorts, physicaly turn 3 or 4 (one of them, NOT both) end for end - so the short hood faces the oppositew way it was facing when it shorted. If it no longer shorts - it's the couplers. You can file down the mounts and put the Kadee couplers in their own draft gear box, or you can also get the same style Kadee but with an insulated shank.
Athear style locos all have the frame grounded to one side of the pickups. Attach a metal coupler to the stock metal tab on the frame, and dependon on which way the locos each face, you have a short. Not the greatest short until some tension is placed on the couplers - think of a wire laying loose on a contact, it might sort of conduct power, but when you press it into firm contact, now it works for sure.
Normally you are fine if they are all put on the same way - all short hood forward, for example. But usually in a consist you want to have the rear loco facing the other way, so at the end of the line, the crew can just swap ends and you don;t have to turn the locos. If it shorts when they all face the same way, what probbaly happened is that on one of the dummys you converted, you put the trucks on the wrong way - front truck on the rear of the loco, etc. If it shorts only when one is reversed, then all is good with the install and wiring, and it's just the metal couplers in the metal coupler boxes attached to the frame.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I thought about the couplers too, so I ran all 4 loco's but each were separated by 2 inches on the test track and NOT coupled together. The 4th loco (the one that keeps shorting) still caused a short reading on my throttle and caused all 4 engines to stop. All were facing the same direction. So, I don't see how the couplers could be the problem. I have not tried to reverse the last loco, and will also check the truck placement again too. Thanks.
Well if it shorts not coupled to anything, then it's definitely not the couplers.
Are you getting a short indication, the walking o's, or overload, the walking I's?
There should be plenty of power to run 4 Athearn locos at the same time.
Does this only happen with the offender added last? What happens if you add loco 1, then 2, then 4 (before 3), then 3?
Paul
Modeling HO with a transition era UP bent
Randy, I think walking o's. You'd think after 35 years in the hobby I whould know enough about model trains to be just dangerous, but I am stumped about the trucks and I'm beginning to think that is the problem. I only learned last year there was a front and rear set of trucks (at least from Athearn) that are sold, either separatly or together in a package. Assuming for a minute I don't know the difference looking at a set of used ones, how do you tell? There is only one way to lay the frame down onto the truck plates, yes?? Otherwise you can't get the trucks "inserted" under the frame. What should I be looking for? I have some new sets still unopened, but they are for F7's and GP7's. I need ones for the GP38's. Maybe I can use them??
Thanks JRP
I'm guessing you are using Athearn old Blue Box locos. Per the BB instruction sheet, F-7, GP-35, GP-7/9 power truck front #42010, power truck rear #42020, power trucks front and rear as a set #42011. With the frame facing away from you (look for the head light bracket), the upright contact bar on the trucks should be on your right. I can not see any numbers on the trucks. If you reverse the trucks, front to back, then the truck upright contact bar will be on the left side. In DC this will make that loco run in the opposite direction (reverse polarity) as other locos. If you use two rear trucks on the same frame or two front trucks, it will have one upright contact bar on the right and one on the left, NOT A GOOD THING! If it is a front truck- with the gear tower facing away from you, the upright contact bar is on your right side. If it is a rear truck- with the gear tower facing you, the contact bar is also on your right side. If your not sure for some reason, which end had the headlight bracket fasten to the frame, the motor's brushes will be on the forward facing end of the motor, so the truck upright connection bars will be on the right side of the frame.
Would I be correct to say you have one of the decoder's pickup wire connected to both trucks upright contact bar and one pickup wire screwed to the frame (red and black to the track)?
Yes, correct. I'm using a BB loco and have red pickups connected to both truck upright bars but I have two black pickup wires screwed to the frame (becuase I changed decoders to the ECO-PNP flat decoder that has 2 left rail pickup connections on the decoder, one in front and one in the rear). I opened new boxes of an Athearn front and rear truck and re-connected everything. Much better running now with hardly any "walking o's on the throttle when I ran all 4 loco's together, but still have walking o's occasionally. Might be because I still have metal screws holding in my Kadee couplers. I can glue them on, but would prefer to use insulated screws if they are available (or plastic ones)?
It appears they no longer sell the ones with the plastic shank. They have plastic head versions though. For example, #38 is a plastic #5 (medium length center shank)
Thanks everyone for your information! Keep those trains running.
Kadee #256 nylon screw 2-56x1/2''. I do not recall any Kadee coupler box that did not have a sleeve in the box to insulate the coupler shank from a coupler box metal screw. But, had someone cut off the rear of a #5 box to fit for what ever reason, or the Kadee coupler #380 (discontinued) with a coil spring to center it, with an open rear end, then the coupler rear end could/will hit the metal frame on compression and short out the system though the second attached loco. if running the locos double headed rear to rear and the locos. runs up on each other (compression of the couplers).