United Traction Trolley electrical pickups

[Rluke]

We have this old Bachmann G scale United Traction trolley that suddenly quit working.   Traced the issue to a pair of electrical pickups both on the same side.  These are a kind of spring loaded piston assembly that contacts the inside of the wheels.  They are mounted in the mudguard frame.
Questions:  What would cause these to quit conducting electric current?  And is there any place to buy replacements?

thanks
Rich

[Loco Bill Canelos]

Hi,

The two main reasons why these might fail are: 1 the spring inside has failed and does not push the brush against the wheel, or 2 the brush is worn out.

Sometimes accumulated grime may not allow the spring to push hard enough on the brushes.  use a tiny screwdriver to see if the spring is okay and pushes the brush against the wheels.  If the springs push the brush firmly against wheel, then the problem may be elsewhere.

You might also try a little conductive lube to the piston area.

I would contact parts to see what is available, click on the tab above to get the contact info!

Loco Bill

[Rluke]

Loco Bill
Thanks for the reply.  The spring is kind of weak but it still contacts the wheel.  I electrically tested the piston assembly by clamping a lead to the exposed piston. No current is reaching to the wire in back of the assembly.    Can you recommend a conductive lube that is really conductive?  That seems to be my only option right now.
Rich

[Loco Bill Canelos]

Rich,

Unfortunately the conductive lube I use is no longer available.

Hopefully someone can suggest an available brand.

If your test had the same result on both piston assemblies, I am thinking the springs may not be making enough contact.  When you did the tests did you press in the piston while doing it??  It is kind of a two way street, the spring puts pressure against the wheel as well as against the brass piston holder.  If the tension is not strong enough they may not conduct.

if you have the piston assembly off the Trolley, pull the piston and spring out of the assembly.  Check for corrosion and the condition of the spring. If the piston is extremely short, or the spring is very weak the they should be replaced.  If the spring is deformed in any way that is the sign there was a short at some point frying the spring.  Another thing to try is to use some plain old track cleaning fluid and swab out the inside of the piston holder. 

Bill

[Rluke]

Thanks Loco Bill for the tips
I have the piston assembly off but I am not sure how to get the piston and spring out of it.  Do I just yank it out with brute force?  Seems there is a hard stop keeping it in.  And if I wanted to replace the piston and spring are they the same size as the ones that Bachmann uses in the truck frame of some of their other rolling stock?

Thanks
Rich

[Loco Bill Canelos]

Rich,

On all the ones I have taken apart, the springs just fell out, so I am not sure what to do.  Any pulling should be gentle, to avoid stretching the spring.
As far as replacements go I believe the the piston assembly are the same but I cannot guarantee it.  You could try squirting some WD-40 or other penetrating oil into the piston holder.

You might want to get the entire assembly and just solder the wire from the old one onto the new one.

Can you call Bachmann Parts and see if they have some from other products?  They were used on the track lighted passenger cars.

Did the other piston assembly on that side fail as well?

Can anyone on the forum help with this??  Anyone have a source for these, other than Bachmann, I do know that USA Trains uses them on their cabooses.  If you call USAT, ask for Mike as he is an expert on their parts.

Best I can do for now


Bill

[Rluke]

Loco Bill
Thanks again for trying to help me with this.  I am not sure if I am describing the assembly correctly.  It consists of the piston and a spring that I cannot see that is contained in an odd shaped plastic housing.  The housing has a sheet metal gasket that screws onto the back.  That is where the wire is soldered to.  The housing is held to the inside of the mudguard with two tiny screws.  It looks like the entire housing was meant to be replaced.  I have never seen that style on any other car.  But of course I am new to all of this.
  And yes the other piston assembly on the same side also failed.  -
Rich

[Loco Bill Canelos]

Rich,

That does seem different than I thought it was. Can you post a picture of yours, as I still can't get my head around the description??

It can be difficult to diagnose a problem without seeing it.

Bill

[Rluke]

Not sure how to post a photo.  Trying to attach this pdf again and it says the upload folder is full. 

[willis]

does it look like a small wheel rolls against the back of the drive wheels?
willis.

[Loco Bill Canelos]

Rich,

You have to post the photo to a photo hosting site, then paste the link in your message.  Bill

[Rluke]

Thanks
It's a cylinder that contains the piston and spring.  The cylinder has "extensions"  on either side that have the holes for mounting.
I had contacted the parts department and just received a reply that they do not carry that part.  Have to buy the entire motor block.  -ouch!