# Fitting the BBT gearbox into a Bachmann "Connie".



## TonyWalsham (Jan 2, 2008)

I recently finished off an installation of the BBT gearbox into the Bachmann "Connie".

The installation went pretty much as the well written and comprehensive instructions outline, so I won't go into too much detail.

A couple of observations are in order though.

Whatever you do, DO NOT[/b] mislay any of the screws when removing the boiler from the chassis and then dismantling the drive mechanism to remove axle # 3. Very carefully store them away in cups or plastic bags.

Do thoroughly smooth down the gear knurling after removing the old gear so the replacement gear can slide on OK. Gordon Watson of Argyle Locomotive was kind enough to turn these down for me.
Do file a reasonably sized D flat on the axle. I didn't and at first relied on a small dimple for the end of the grub screw to run into.
Even though the screw was Loctited, this did not work, and it still came loose enough on the shaft enough to allow the gear to rotate on the axle. A real pain to fix necessitating I once again remove axle # 3 from the chassis. I managed to do this without having to remove the body shell.
Moral of the story. Make absolutely sure the screw holding the gear in position on the axle is TIGHT[/b] and cannot come undone. 

Do replace all the counterweight screws with the supplied stainless steel ones and Loctite them in. Even though the screws were tight, the counterweights still could rotate very slightly. It is a good idea to test the chassis for binds without the gearbox fitted. Gently twist the counterweights to remove any binds. I got lucky the assembly was pretty well spot on.

Here are a couple of pics not included with the instructions which may prove useful.










Be sure to add the clear plastic spacer to the rear of the gearbox to stop the newly mounted assembly from flip flopping backwards too much when running.

The mechanism should sit squarely with the motor parallel to the chassis.










In order for the near gearbox assembly to fit up into the boiler some of the lower boiler plastic must be removed.
BBT have provided a pretty accurate stencil which I cut out and glued in position on the underneath of the boiler.
It is most important that the black line drawn on the centre of the stencil is placed accurately in line with mould parting line on the centre of the underside of the boiler.
Yes, I know the majority of the hole is well off centre.










I carefully drilled out some access points along an edge and cut away the plastic boiler material with a small hacksaw blade I had removed from the hacksaw. I also removed the holding pin from the blade to make life easy.
Take your time and work carefully. You will probably need to file a bit here and there to allow the body to fit down over the chassis.










You will need to take out about 1/8" from the cab floor as well.
Part of the installation process is to remove the iron weight from in front of the cab.
I replaced this with a bunch of stick on lead wheel weights. I also added some weight to the front pony truck which can derail on rough track.

Once it was all reassembled I was eager to get it tested. 
It runs very well now. There is a very slight bind in reverse that Barry assures me will gradually disappear when the mechanism is bedded in. I do know that after 1 hour of running it was much smoother.

The loco is to be delivered to the owner in a couple of weeks when I am next in Brisbane. It will prove to be a powerful puller and much smoother runner than it was. 

A follow up report will be forthcoming.


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## aceinspp (Jan 2, 2008)

Looks like a nice clean install. Looks like a lot of work also, especially removing the boiler. Thanks for the extra advise. May need it someday if I ever decide to redo mine. Later RJD


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## TonyWalsham (Jan 2, 2008)

I must admit I was daunted by the prospect when I first got the gearbox and loco in. Eventually I simply got started because it has to be delivered in a couple of weeks. 

It is a bit fiddly but nothing someone with some experience in working on Large Scale locos could not handle. 

However, I would not recommend the install to a first time novice.


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## aceinspp (Jan 2, 2008)

I'd agree with that. I took mine apart to install a DCC board so I know the drill on this one. While I did have it apart I did check to make sure the gears where working as they should be. basic tune up. Later RJD


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## TonyWalsham (Jan 2, 2008)

This particular loco was actually running. 
The axle gear had not actually cracked all the way through. Sooner or later it would and then there would have been no drive at all.


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