Large Scale Central

Connecting 2 bachmann drive units?

Electronics
#1

The Garrett build is coming along and I’m at the point where I want to connect the 2 bachmann drive units so all wheels will act as pickups. I don’t want one unit to stall and have the other sill chug along possibly damaging gears.

Investigating the 4-6-0 annie chasis there are plugs at the back and I wonder if I can use the bachmann plug and wires and tie those together inside the center boiler and connect them when in use?

Here is a wiring diagram from Bachmann

http://www.bachmanntrains.com/home-usa/dwg/dwgs/LS_4-6-0_Metal_Gears.dc_wiring.pdf

One side of the plug goes to the chuff sensors and heads back to the sound unit in the tender. The other goes to the motors and track power pickups.

Would there be any issue with connecting the 2 motor chasis via the bachmann power plugs and linking the 2 engines together?

I don’t think so but stop me before I blow something up!

#2

A bit more testing and I found that if the track has 10 volts the plug in the back of the chasis has 8 volts. I’m assuming that the loss is when the current goes through the motor.

I think I can link the motors between the plugs in the back. Both units will be on the powered track and linking them together even with the loss of volts should keep both motors turning even if one should lose track contact due to dirty track etc.

#3

I would say the loss is probably from the pick ups. And yes, if you match the polarities then it should work.

#4

You might think about adding some kind of capacitor to store energy to carry the motors across dirty or bad track and joints.

#5

The socket that does not go to the chuff contacts gets full track voltage…

The voltage you are measuring is not lower because you are measuring it through the motor, you are measuring across the motor.

Yes you should be able to use that socket to connect the two locos together, but I would take the direction switch out of the circuit, or lock both in place so they cannot be reversed.

Since you have connected all the track pickups together, this should have better power pickup and of course a longer wheelbase, so there should be no need for additional pickups or storage capacitors. You normally need this when you have fewer pickups or a short wheelbase, and you have the opposite of both situations.

Greg