Anyone using metal truck frames?

[kenkal]

Recived a # of cars froma friend.  Put them on my DCC layout to see how they looked and ran.  immediately got a short when they derailed crossing turnout.

Which raises the question of does anyone use these things anymore? And why don't they short out on DC as well, not just DCC?   Seems to me the metal axles should short out immediately since they are connected to the metal frames.  What am I missing here????

Thanks.  Ken

[NeO6874]

I have used a few metal frames (Kadee) that have not shorted anything out -- HOWEVER the wheelsets I use have at the worst a plastic shim on one side to keep the wheel from contacting the truck frame (and the metal axle), though the newer ones have plastic (nylon or delrin?) axles and axle points..

[gandydancer19]

I actually prefer the metal Kadee trucks. They run better and the springs allow them to equalize and follow the track work better because they can flex, unlike stiff plastic trucks.

If they are derailing on your layout, either the wheel gauge is not correct or your track work leaves something to be desired. Check EVERYTHING with an NMRA track and wheel gauge and correct the problems. Also, look for dips in height of the track.

Central Valley (the old company, not CVT now) made metal trucks 40 years ago. They were good for their time, but don't come close to the metal Kadee trucks of today. If you have those, you will need to work on them to make sure they are free and the wheels aren't shorting.

[jrbernier]

Ken - I have had no problem with metal trucks.  They will short if they derail on a turnout.  The 'short' is much worse on DCC because you typically have 5 amps of power at the booster, and high voltage on the track at all times.

  As far as running qualities - most 'sprung' trucks are way too stiff to provide 'equalization' and the springs look way too small to look correct(at least to me).

Jim

[Texas Zepher]

Recived a # of cars froma friend.  Put them on my DCC layout to see how they looked and ran.  immediately got a short when they derailed crossing turnout.

Which raises the question of does anyone use these things anymore?

Not by choice.  The smooth self lubricating plastics that are available today are wonderful for needle point axles.  I have a set of Hallmark passenger cars.  I had to go to double insulated wheel sets to keep from shorting just going around 36" radius curves.

And why don't they short out on DC as well, not just DCC?

For the most part they do. It is just not as noticable.  1.  As a prior poster noted in DCC there is constant voltage applied to the rails.  2. The voltage as high (or higher) than a DC at full throttle.  3. There is a higher current in the power that is constantly on the rails.  3. DCC is a bi-polar high frequency so the power can actually "jump" very small gaps (much like a capacitor of the correct value will "pass" high frequency AC signals).  

Seems to me the metal axles should short out immediately since they are connected to the metal frames.  What am I missing here????

One or both of the metal wheels are inslutated from the axles.  That is why the special double insulated ones I purchased for my brass passenger cars helped so much.  If only one of the wheels is insulated then the truck is "hot".  SO, if a car is immediately shorting when put onto the track, check to make certain one of the wheel sets is not in the truck opposite of the other.  That is, both insulated wheels must be on the same side.

The more metal anything one adds, metal wheels, metal axles, metal bodies (like brass), the more frequently short circuits will occur.  DC or DCC. 

[loathar]

My plastic truck framed cars short out on derailments too sometimes. I haven't really noticed if the metal ones are more prone to shorts that the plastic. Just make sure they don't derail!

[kenkal]

Thanks for the explanations, Texas.  Makes sense what you said.  Ken

[kenkal]

Well, those metal frames sure seem to make for a pretty fireworks show when they derail in night scenes.  I'm sure it doesn't help the DCC system though. Ken