Bachmann Berkshire trailing truck axle length....

[Dirk Jan Blikkendaal]

Can someone measure the axle length of the trailing truck wheelsets of the N scale BACHMANN Berkshire?
I removed the cones from my 2 engines......
Need the axle length to design a B&M Lima Berkshire trailing truck.

Thanks in advance, Dirk Blikkendaal

[jbcz]

I built a credible B&M Berkshire with a Kato Mikado and a trailing truck from Keystone Details.  I saw mention of it from another post by Lemosteam.  I had to cut and file it a little to make it fit my implementation but after that it works great with no impact on Mikado performance.  The wheel spacing seems like about 102" which is just right for the Berk.  Here's how it looks.

[Dirk Jan Blikkendaal]

Thanks and nice idea/work but I need the axle LENGTH (not spacing). Lemosteam offered to see if an adaption to his LL Berkshire trailing truck is easy to do.....

[jbcz]

I sort of missed the point.  My only point was that you may not have to design a new trailing truck but simply adapt the one that I used.

I used a Kato trailing truck wheelset for the larger wheels and a random wheelset for the smaller wheels since they were close to the proper diameters.  I am no kit-bashing expert but do close enoughs that are simple and picked those wheelsets because the "worked".  The wheelsets worked well with a slight amount of reaming in the holes of the trailing truck.  Their length point to point was .577".

[Dirk Jan Blikkendaal]

I would still like to know if someone can measure the Bachmann trailing truck wheelsets axle length.
Because I use the Bachmann Berkshire as a base those wheelsets are at hand......

BTW, its not designing a new truck: Lemosteam offered to just adapt his existing Shapeways LL Berkshire trailing truck (that design is exactly right) to Bachmann axle length ..... I guess just a small job.

I agree that close enough I good enough.....also for me.....

All help much appreciated!

[Lemosteam]

Calling @SkipGear ...

[reinhardtjh]

Can someone measure the axle length of the trailing truck wheelsets of the N scale BACHMANN Berkshire?
I removed the cones from my 2 engines......
Need the axle length to design a B&M Lima Berkshire trailing truck.

Thanks in advance, Dirk Blikkendaal

The axles don't have a point bearing.  They use an internal bearing block.  The axles are 11.8mm face to face and 7.55mm between the inside faces.  The bearing block is 5.5mm wide.  Also the axles are on a 12.4mm center to center distance.

[SkipGear]

Calling @SkipGear ...

Busy day at the shop today. Looks like John covered it pretty well.

[narrowminded]

In case it matters, 7.55mm wheel back clearance noted on that picture is the NMRA standards minimum.  The range is 7.7mm maximum and 7.55mm minimum.

[Dirk Jan Blikkendaal]

Thanks a lot and very helpful!
I must be getting old....... in my recollection I removed the cones because the Bachmann wheelsets did not fit the LL Berk 3D print from Lemosteam... which is impossible if they are not there.....
I do hope John has a bright idea how to solve this problem .
If not, just leave it John...... with the pictures and description I made a modeler should be able to adapt your nice LL Berkshire trailing truck 3D print to my Bachmann B&M/SP/ATSF conversion.

Regards, Dirk Blikkendaal

[Lemosteam]

The axles don't have a point bearing.  They use an internal bearing block.  The axles are 11.8mm face to face and 7.55mm between the inside faces.  The bearing block is 5.5mm wide.  Also the axles are on a 12.4mm center to center distance.

@Dirk Jan Blikkendaal , did any of the ATSF receive the lima drive engine behind the truck?

@reinhardtjh , Would you be willing to remove the truck and make some additional measurements A-J?  Also share a picture of the top of the truck.  If not I understand.  Is the truck electrified?  Looks like the wheels are fully insulated and I can't see any pickups in your image.

A: width thickness and top surface (opposite side of photo) doe to the railhead

Remaining measurements are self explanatory in the pic below:

@SkipGear, thanks anyway!

[Dirk Jan Blikkendaal]

John,

Thanks....
As far as my knowledge goes all trailing truck drives were removed already before going to SF.
I believe there is no room for it anyway due to the pin for the tender drawbar protruding from the chassis behind the trialing truck.

See the attached picture of my adapted truck.
You basically only need the 2 side frames and the flat crossbearer + drawbar connection with the last screw in the driving axle coverplate.

That attachment might pose a problem if printed in 3D (prone to breaking).... the OD of the tube holding the last cover plate screw is 2.5 mm as I measure.
The free space around it has a diameter of just 4.0 mm..... so the ring at the end of the drawbar can be 0.75 mm max with a thickness of 1.5 mm max......   

The underside of the connecting lip has to be 2.6 mm above railhead and the top can be 4.1 mm above railhead max.....

other measures:
A  ??
B 8.5 mm
G 7.55 mm wheelbackside (6.6 mm between plastic sleeves) [ Guests cannot view attachments ] [ Guests cannot view attachments ]
I 5.6 mm
H 6.5 mm
axles 1 mm diameter

all 4 wheels on plastic sleeves so no elctrical contacts possible.

I do hope everything clear.... regards, Dirk

[reinhardtjh]

@Dirk Jan Blikkendaal , did any of the ATSF receive the lima drive engine behind the truck?

@reinhardtjh , Would you be willing to remove the truck and make some additional measurements A-J?  Also share a picture of the top of the truck.  If not I understand.  Is the truck electrified?  Looks like the wheels are fully insulated and I can't see any pickups in your image.

A: width thickness and top surface (opposite side of photo) doe to the railhead

Remaining measurements are self explanatory in the pic below:

Here's attempt #2 at providing dimensions.  Note the dimensions for the radius of the tongue and the hole are reversed.  Preview won't let me fix it and I'm not starting from scratch again (yeah, again).  As for the other questions, the truck is not electrified. There is no power pickup.  The axles are fully insulated.  The truck frame itself is black painted metal.  The tab that clips on to hold the axles is plastic, seems to be a Delrin type, probably for a bearing.  The piece through the middle that the axles rest on is sloped since the trailing wheel is larger than the leading wheel.

Bottom View:


Side View:


Top View (just for completeness):

[Lemosteam]

Thanks @reinhardtjh !