Bachmann 70 tonner diesel
#1
Hi,
I've recently used the chassis from a bachmann 70 tonner as the basis for a scratchbuilt Alco ingersoll/Rand boxcab but when running the noise level from the motor is a bit high........is there anyway I can tweak the onboard Bachmann chip to quieten the motor noise, or is it possible to replace the Bachmann chip with another makers to achieve silent running?

   
Cheers,
John

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#2
Have you checked all the moving parts to see if it's mechanical related?
Tom

Model Conrail

PM me to get a hold of me.
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#3
Hi,
Yes.....I know there's a few little gears in there but it's definitely motor noise.....not terrifically loud, just annoying :?
Cheers,
John

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#4
First off,

Wow! That's a really nice model!!!

The empty shell may be amplifying the sound from the motor.

Perhaps you could try packing some soft foam between the shell and both sides of the motor to dampen the sound...
Ron Wm. Hurlbut
Toronto, Ontario, Dominion of Canada
Ontario Narrow Gauge Show
Humber Valley & Simcoe Railway Blog
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#5
Replace the Bachmann decoder, it's not a silent running decoder. Also, clip off the capacitors that are in parallel to the motor. ENd result will be MUCH quieter.

--Randy
Modeling the Reading Railroad of the 1950's in HO

Visit my web site to see layout progress and other information:
http://www.readingeastpenn.com
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#6
Thanks for that Randy Thumbsup , funnily enough I was looking at a silent running decoder on e-bay the other night wondering if it would be the answer ....I think it was for a Proto 2000 loco (but I could be wrong) .....I'll have to go back and have another look.
Cheers,
John

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#7
Yep, Randy pegged it. That basic decoder that's in there now is functional, but anything but "silent".

Any decent contemporary decoder should give you good quiet running, since the drive is actually quite good in those 70 tonners. I installed an ESU LokSound unit in ours, and it runs and sounds very good.

Something to watch for, though, is that these units are prone to the splitting-axle problem that plagued a lot of Life-Like/Walthers locos... the axle cracks making the gears out of round, and the loco will grind and bump its way down the track.
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#8
A board form factor decoder for a Proto 2000 loco probably won;t be an easy fit. Here's a good how-to from the TCS web site: http://www.tcsdcc.com/Customer_Content/I...GE_70.html

I'd also remove those capacitors (the little yellow blobs around the motor) if yours has them. They interfere with proper operation of a good decoder. Just clip them all off (but don't cut the motor itself).

Even though they were gone by my era, I always liked those AGEIR boxcabs. I've had several of the MDC versions, never thought to repalce the noisy mechanism with the 70 tonner. Looks liek maybe I need to aquire another.

--Randy
Modeling the Reading Railroad of the 1950's in HO

Visit my web site to see layout progress and other information:
http://www.readingeastpenn.com
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#9
Many thanks for all of your help guys Thumbsup , I'm now a lot more sure of what to do to rectify the problem.

Randy :- Re: the boxcab, being as I built it from scratch I stretched the body slightly to fit the 70 tonner mechanism (which has the wrong wheelbase) so I'd check the MDC body carefully. I suppose the chassis from the Bachmann 40tonner might do as well, but the wheelbase for that isn't quite boxcab friendly either.
Cheers,
John

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#10
Re the 70-tonner chassis - I have some of the Roundhouse/MDC bodies for use on my Erie RR 149th Street Harlem Station layout, but went down a different powering route. Bachmann UK made some cartoon-character, underground trains to co-incide with a TV series called "Underground Ernie, and you will find the locos still available on Ebay.uk . If you remove the moving-eye mechanism, and make a new Plastic card base to fit around the mech and into the underside of the body, although there is only one powered bogie (they pick up on the other), they are quiet and run very well. They benefit from a sheet of lead under the roof, and I filed down the sides of the plastic bogies, cast some new ones in car body filler resin (using the sides of a 44/70 tonner to make the mould in modelling clay), and then epoxied those to the sides of the bogie frame. A lick of matte black paint and they look, and work, fine. BTW if you decide to go this route, don't use the inspection car - it has a complerely different single bogie mechanism - suitable for 4-wheel critters, but not for the boxcabs.
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#11
Since I'd never heard of that TV series, I had to look it up. And found several UK vendors selling the Bachmann models new in the box for a very reaosnable price. One site even showed them fully disassembled, touting their use as drive sources for other projects. They had both the inspection car and a regular car. I can see how that would work out pretty good. Just what I need, another project. To make a correct model I would have to do quite a bit of modification to the MDC body, the stock version does not have the correct radiator system as used on either of the two Reading units.

--Randy
Modeling the Reading Railroad of the 1950's in HO

Visit my web site to see layout progress and other information:
http://www.readingeastpenn.com
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#12
Randy - to give you a bit more idea - this is a chassis with the original bogies

[Image: dscn1953d.jpg]

The boxcab on the modified chassis - looks as though the ends and kadees need tightening up!

[Image: dscn1949r.jpg]

Modified chassis with modified bogies

[Image: dscn1950o.jpg]

Uploaded with ImageShack.us

The chassis with no body from a slightly raised position showing motor and worm drive

[Image: dscn1951.jpg]



Chassis under side showing powered and un powered bogies - note that both bogies pick up, but the powered one has traction tires on one driven set of wheels

[Image: dscn1952x.jpg]


The body has sheet lead stuck inside the roof - the complete unit weighs about 200gms (7 oz). Hope the info helps
Jack
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