The Bachmann SD40-2 has landed

[spookshow]

I took the ESU decoder out of my Atlas FA-1 and put it into my SD40-2. I got lights and sound, but no motor. So I guess TrainWorld was right after all - these Bachmann motors really can't handle extended running 

-Mark

[bbunge]

I took the ESU decoder out of my Atlas FA-1 and put it into my SD40-2. I got lights and sound, but no motor. So I guess TrainWorld was right after all - these Bachmann motors really can't handle extended running 

-Mark

My Ntrak modules have a "green line" loop, about 20 feet of track total, that can run either DC or DCC depending how I set it up.  My go to locomotive is a recent run Bachmann F7.  It pulls well, it was cheap ($50 off Fleabay a number of years ago), it tracks well on not so great track with a steep grade and 6.5 inch radius curves.  When we set up at the B&O RR museum over the holidays it will get about 50 hours of run time - 6-8 hours per day.  At a Timonium show it will see at least 12 hours of running, 2-3 times a year.  After maybe three years of this use, the motor died.  I ordered another, installed it.  After another three years, this year, after about 35 hours it was acting flakey - the light turned off and started to run slow at certain spots on the loop, even after the track was cleaned.  I let it rest for two hours, cleaned the wheels and it started right up again.  I haven't had a chance to look at it yet.

There is also 2.5 feet of back and forth street car track that gets the same hours.  My recent go to for this is a completely tore down and rebuilt Tomytec TR04 chassis.  The prior go to is a cleaned and somewhat rebuilt Kato 11-106 chassis.  Both take a lot of hours, but do slow down after many hours, often with dirt on the wheels, so I end up swapping them out.

Bob

[brill27mcb]

What prompted the need to tear down and rebuild the Tomytec chassis?

Rich K.

[bbunge]

What prompted the need to tear down and rebuild the Tomytec chassis?

Rich K.

A complete clumsy moment: I knocked over a bottle of H&N Solder flux on it.  After cleaning it off, it was apparent it wasn't going to run well, so I put it in a box and replaced it with a new unit.

Later, I needed a chassis, so it got stripped down as far I could.  I had recently read through Ron Bearden's thread on rebuilding the Bi-Polar units so I was inspired to buff shafts and polish gear center holes/bushings with a tooth pick, etc.  I borrowed from Peteski and polished electrical contacts since the flux had tarnished the metal.  I also experimented with bushings and gear centers by rubbing a toothpick in Microtrains "Grease 'em" and then rubbing the toothpick in the gear centers.  I burnished some of the gear teeth with the dry-lube toothpick as well.

I was really pleased, the unit runs real slow, quite a bit slower then the out of the box version.  Most important it is more reliable starting at a low voltage.  I believe the next step would be to re-motor it with a gear head so it would start at an overall higher voltage.  A Shapeways Brill shell that is to scale is on it, so there is very little room for additional weight to help with electrical contact.

[randgust]

Wow, Mark, it's been a long time since you've awarded an "F".   

As one of the old N scale guard, I'm still insisting that a locomotive actually pull something, not just look pretty and sound good.   

You can really appreciate the detail if it can't move and just sits there, possibly spinning.   Or the only sound is accurate engine idle.

It's funny because I designed my layout in 1983 when three Trix U-boat chassis could easily handle 25 cars up a 2.5% grade and around a 13" 180-degree curve at the summit.   No problem.   Original Kato SD45's, SD40's, U-boats all can too.   Now it's a challenge with anything new.   And I can't remember ever burning a Kato motor out.   Ever.  And my old Trix units wore the plating off the wheels, then they really pulled!

[peteski]

Judging by the exploded parts diagram on Spookshow's website, these appear to be using one of the inexpensive coreless motors Bachmann and other manufacturers started using several years ago.  Those motors usually only have 3-winding baskets and flimsy thin metal whisker brushes. "Real" (expensive) coreless motors use precious metal commutators and brushes for long life.  I do not expect those inexpensive motors to have a long life, unlike the old-fashion open frame motors with carbon brushes which were the staple of Atlas, Kato and many other manufacturers for decades.  However if the motor is what actually failed, I am surprised that it only took 12 hours of running.  Maybe that model has a high-friction mechanism which puts a high load on the motor?

As for Kato motors, I have seen one which was still running but close to failing due to a worn out commutator. Yes, the commutator was worn down while the brushes still had plenty of "meat" on them.  But that model had a very hard life of many hundreds of hours of roundy-round operation.

BTW, I re-read Mark's review of this loco and I had to chuckles at the original ('80s) review of the model. Price: $22!  Now that's when Bachmann really made inexpensive low-end N scale locomotives and priced them accordingly. 

[spookshow]

Wow, Mark, it's been a long time since you've awarded an "F".   

Not that long ago, actually. I was even more unhappy with BLI's 2023 Big Boy. What a fiasco.

-Mark

[spookshow]

As these things find their way into the wild, I'll be curious to see if it was 12 hours of continuous running that killed mine, or just 12 total hours of running period. If the latter, this could be the most epic of Bachmann's epic fails.

-Mark

[track1]

Mark,

Sorry to hear that you ended up with two defective SD40-2s in a row. After reading your post, I ran a production sample for nearly 24 hours on our test layout, with an 8 car train, and it ran without issues. Which roadname/SKU did you purchase?

We certainly hope this isn't a much larger issue- we'll be monitoring this thread as well as feedback to our customer service department.

Thanks,
Tyler
Bachmann R&D

[spookshow]

Both were Union Pacific (67077). The first one failed when I left it running overnight and tried to change directions the following morning. The second one simply stopped running during the night. Both appear to have been motor failures, although I did not dissect them in order to scientifically verify that theory.

-Mark