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Fitting additional pick ups to bogie/pony wheels (steam loco)


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I have done a search but can only find threads relating to this for diesel models.

 

I have a Bachmann 3MT 2-6-2T, this model does not have a centre sprung axle, ie. 3 rigid axles,

so to improve electrical wheel /rail contact I'm considering fitting extra pickups to the front pony wheels.

 

How sucessful is this likely to be re. improving the running, and what is the method, mechanically speaking of fitting them, allowing for the pony wheels to pivot, as well as the axle to slide from side to side?

 

Is it best to position the pick ups to contact the backs of the wheels or have them contact the tops of the wheel tread?

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I may be off target here but I offer this comment just in case.  I have a Bachmann 2MT tank (2-6-2 - split chassis) and it already has pickups on the front pony truck.  However, it was always a dodgy runner - until I discovered that the metal parts holding the wheels, and to which the wires were soldered, were painted all over, thus insulating them from the wheels through which pickup was supposed to operate.  Cleaning off the paint where appropriate cured the problem.  The model I have is catalogue number 41-241 from which you can probably gauge its age.

 

As I say, sorry if this is irrelevant.

 

Harold.

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Let's start from the beginning, Have you made an attempt to optimise pick up from the coupled wheels? Adjusting the wipers for constant positive pressure can make a major difference: if they don't stick out at a 45 degree angle from the chassis side with the wheels removed, then bend them out like that and refit the wheelsets.

 

If the driven axles other than the gear driven axle are very tight in their bearings, leaving the keeper plate screws slightly slack - maybe half a turn before fully 'home' - can be enough to allow the axles that bit of extra vertical movement for better rail contact.

 

Adding a spring to unsprung driven axles is not impossible. A slot along the centreline of the chassis block underside can admit a leaf spring, clamped in place by a plastic block under the keeper plate near a securing screw.

 

 

How sucessful is this likely to be re. improving the running, and what is the method, mechanically speaking of fitting them, allowing for the pony wheels to pivot, as well as the axle to slide from side to side?

 

Is it best to position the pick ups to contact the backs of the wheels or have them contact the tops of the wheel tread?

Wipers on unpowered wheelsets are brakes reducing the pulling power of the loco as they introduce drag which has to be overcome from traction on the rail. (On powered wheels they impose no such penalty, provided the motor has adequate power to slip the wheels on the track when the loco is held back.)  If they are to be used it is generally best to have them bear on the wheel back behind the flange and tyre, on the tread they will accumulate dirt and need regular cleaning. Wipers may be directly screw attached to a plastic frame using small self tappers.

 

Continuing from what Harold mentions concerning the old Bachmann split chassis steam models. If you have any suitable carrying wheelsets from these or other sources that are split axle, then the lower friction option of pick up from the stub axle bearings is available. No incremental friction over the bearing that has to be present, and which can be kept lubricated relatively easily with a conductive grease or graphite.

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Hi Philsandy

 

You may find some interest in my recent Blog Post about fitting a bogie with wipers to an old Mainline loco.  If you don't feel up to making your own wipers, there are proprietary bogies out there already - either as spares or to be 'borrowed' from a used model.

 

Ray

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Thanks for all your replies.

 

Plenty to go on there.

 

34C, I will try slackening the keeper plate screws first. The existing pick ups are correct and fully tensioned.

Ray, your blog has given me some good pointers on how to fit the additional pick ups.

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