N Scale B-mann "MDT"

[brokemoto]

Everything that I have read about this locomotive suggests that there really was no prototype for it.  It does look much like a two axle locomotive that Plymouth offered but the dimensions are much smaller.  The model would have to be a WDT, as Plymouth had that designation for the three axle.  The N scale version  might actually work as an HOn30 switcher.

If there actually were a prototype for it, I am guessing that it might have the following specifications:

40-6o tons

200-325 HP six cylinder diesel.

Available with hydraulic, mechanical or electric transmission.

Available with one, two or three traction motors for electric transmission. 

Available with chain drive or gears for one, two or three axles or as  many idlers as the user ordered, regardless of transmission ordered.

15-20.000  lbs. tractive effort with 300/325HP diesel and .three traction motors.  Less for other combinations.

Why am I asking this?

I have two of these. One is the second to last plastic box version of Chinese manufacture,  prior to  the better motor and working knuckle couplers.  The other is a hybrid.  It is one of the last Hong Kong versions, with a split metal frame and the open three pole motor.  What makes it a "hybrid" is that I swapped out the cracked white gear axles for the black gear axles of Chinese manufacture   They came from two that I bought from a guy at a Timonium Show.  He had several on his table.  They would not run, so he was selling them for five dollars each. I bought two.

I hardwired each of these to an electrically live  four wheel JNR brakemen's van that I doctored up a bit to make them appear North American.   Th Chinese locomotive runs well.  The real gem is the Hong Kong/China "hybrid".  The slow speed control is excellent.  The pulling power is not bad:  eight freight cars and a B-mann four wheel caboose on straight and level or thirteen and three quarters curves.

I want to use these in operations but they would have to represent a fictitious Plymouth prototype that has about a 300HP engine, three traction motors and fifteen to twenty thousand pounds of tractive effort.

It is somewhat shorter than the B-mann 44 tonner but a bit higher.  The hood on the MDT/WDT is slightly longer than either hood on the 44 tonner.  The MDT/WDT sits a bit higher.  The hood on the WDT/MDT is a bit wider or bulkier than the 44 tonner.

Would the specifications  be realistic given the dimensions of this WDT/MDT?

[kiwi_al]

It looks like Bachmann put 3 axles under a MDT design, possibly loosely based on:

http://www.rrpicturearchives.net/showPicture.aspx?id=2328530

The EBT WDT (maybe an MDT - seems to have 2 axles not 3) is close from the back 3/4 view but it's not a clear picture. I have 2 Bachmann WDT (one old and one of the newer ones)

[brokemoto]

The EBT WDT

A B-unit....................  fascinating!  [hear gears grinding and smell wood burning in head].  The Timonium show is this weekend.  Time to buy some shells from someone's junk pile.  I have an electrically  live unpowered chassis that I can cut down to accommodate a bashed B.  I then can hardwire it to a powered unit.  THANK YOU!

If you compare the B-mann (or any of the other versions of this) to the photograph, the N scale model appears to be an out-of-scale version of the MDT and on a three axle chassis.  Hence my idea that this could be a "model" of a  fictitious prototype.  The three hundred horsepower diesel is not a reach as Plymouth did offer an MDT with such an engine (I seem to recall that it was a Buda).  I can not find any figures on tractive efforts for MDTs or WDTs but I did find  one for a Plymouth four axle that ran in Southeast Asia.  It had a thirty four thousand or so pound rating. For this reason, I do not consider a tractive effort rating of half to sixty per-cent of that unrealistic.

Plymouth never offered a WDT that looked anything like the B-mann.  Further, every WDT that I have seen as well as the illustrations in the Plymouth catalogue show an inboard suspension while the B-mann has outboard.  Thus, my characterisation of this as a "model" of a fictitious prototype.

[randgust]

I love a good challenge.    Because I could have sworn I found one once.......

So Ill submit this in evidence.....    It's not a Sasquatch or a Unicorn, but it's very tall, furry, and has one horn.



http://abpr.railfan.net/abprphoto.cgi?december07/12-10-07/TeleRR402inHonduras1985Corel.jpg

[daniel_leavitt2000]

It looks like Bachmann put 3 axles under a MDT design, possibly loosely based on:

http://www.rrpicturearchives.net/showPicture.aspx?id=2328530

The EBT WDT (maybe an MDT - seems to have 2 axles not 3) is close from the back 3/4 view but it's not a clear picture. I have 2 Bachmann WDT (one old and one of the newer ones)

If that is a standard scale car, the Bachmann model must be 1.5X scale! I would love critters (GE 25T, MDT, ETC) to be available as printable shells so we could build something scale.

As for the Bachmann MDT, I always thought the chassis has potential as an early boxcab.

[peteski]

Arnold and Minitrix produced some tiny N scale "critters" depicting European prototypes.  Here are couple with a Kato 3-axle truck in the center for size comparison.  Of course these tiny locos don't weight much so electric pickup is not the greatest, and shoehorning a decoder is likely not possible.

[Ed Kapuscinski]

A B-unit....................  fascinating!  [hear gears grinding and smell wood burning in head].  The Timonium show is this weekend.  Time to buy some shells from someone's junk pile.  I have an electrically  live unpowered chassis that I can cut down to accommodate a bashed B.  I then can hardwire it to a powered unit.  THANK YOU!

If you think THAT is interesting... Also at the EBT
https://oldeastie.com/Loco/x4.html

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[randgust]

If that is a standard scale car, the Bachmann model must be 1.5X scale! I would love critters (GE 25T, MDT, ETC) to be available as printable shells so we could build something scale.

There's been a printable Shapeways 25-ton body for a while, I used an incredibly tiny 4-wheel Tsugawa TU7T drive with a Kato 12V motor on it.  It ran....but.... the body really, really, really needs to be metal to have better pickup.   And with a wheelbase that short, if it hits a deep frog, you need seat belts in the cab.    I've driven around  25-tonner myself, and it bucks, but not that hard.

And there's always 'that guy' that wants a decoder and sound in it.    I did about five of these as custom builds and nobody has done one lately.

I am still tinkering with one of the 4WD double-worm horizontal motor mechanisms under same printed body.   

I did a scratchbuilt one years ago, runs better than the Shapeways one, the mechanism is still less than stellar.

My opinion is that the best little critter chassis I've ever seen, hands down, is the Kato 11-108 new one.   Not because it's the smallest, but because they equalized it for the best electrical pickup, and the drive is slow speed and whisper quiet.

[Jim Starbuck]

This is a Shapeways GE 25 tonner with an ESU decoder and TCS keep alive.
Nice running small locomotives are absolutely possible.

[randgust]

What's under the hood, Jim?    I've been playing around with 25-tonner mechanisms forever, and the torque and slow speed remain elusive.

[Jim Starbuck]

What's under the hood, Jim?    I've been playing around with 25-tonner mechanisms forever, and the torque and slow speed remain elusive.

It’s a Japanese narrow gauge turnback drive. The chassis is 3d printed and offered is different axle spacing and wheel size. I think I changed the wheels to Katos. I also remotored it with a 6x15 mm coreless. There are lead wafers in the cab sides and tungsten powder in the hood.

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Here’s a link where I got the chassis.

http://narrow-japan.net/

[randgust]

That's extremely similar to what I'm still tinkering with, but I hadn't thought to go to a 6x15 instead of the stock DC motor.   Since Eldon (Motorman) passed, I don't have a motor source - particularly of a decent voltage.   Sourcing?

[peteski]

That's extremely similar to what I'm still tinkering with, but I hadn't thought to go to a 6x15 instead of the stock DC motor.   Since Eldon (Motorman) passed, I don't have a motor source - particularly of a decent voltage.   Sourcing?

Well, not the Maxxon or Faulhaber quality, but you can get small coreless 12V motors as replacement parts from Kato and Bachmann.  I also buy motors from https://micromotor.eu/ through https://www.dm-toys.de/en/, specifically https://www.dm-toys.de/en/list/manufacturer/MicromotorEU.html They have wide range of sizes available. All 12V motors.

There are also other sources - I'm sure others will chime in with where they get theirs.

[Jim Starbuck]

That's extremely similar to what I'm still tinkering with, but I hadn't thought to go to a 6x15 instead of the stock DC motor.   Since Eldon (Motorman) passed, I don't have a motor source - particularly of a decent voltage.   Sourcing?

This is where I source my motors and have been quite happy with them.

http://tramfabriek.co.uk/

[Dwight in Toronto]

I can endorse Jim’s Tramfabriek referral - I’ve purchased a small coreless motor plus a few other things from this reliable, pleasant-to-deal-with UK-based vendor.  And Jim, kudos man - that is a praiseworthy, wonderful little bit of superb micro-modelling.

Peteski - there’s something about those tiny European two-axle models that is hugely appealing to me.  I can’t quite put my finger on it, but seeing those (and Jim’s 25-tonner) is rejuvenating a fascination and interest that I’ve always had in the “smallest of the small” in N scale. 

Seeing these posts might well have compelled me to divert my focus towards this aspect of the hobby for a while!