OMM-Bachmann 2-8-0 Conversion Kits - Index

 I'm getting enough requests for researching the OwlMtModels (OMM) SP C-8/9/10 conversion kit/parts using Bachmann 2-8-0 that I'm setting up this index page where I can put progress photos, prototype info, and updates.

Stock Bachmann UP 721 with OMM 4013, 4012, and 4015 pre-production parts installed, Jan 2020.

Posted Blogs on Conversion & Research

Kitbashing Bachmann 2-8-0 (Part 1) into SP C-8/9/10 class with OMM Conversion Parts - Prototype research and index of prototype photos, plus prototype roster data.

Kitbashing Bachmann 2-8-0 (Part 2) - Options for Additional Parts - Suggestions for additional detail parts outside of the OMM parts: such as Cal-Scale, Precision Scale Co, Bowser, etc. and a couple examples of parts fitted on my old Bachmann 2-8-0s from 20+ years ago.

Related Articles

Weathering SP Steam Engines (Part 1) - Notes on how to weather distinctive features on SP steam engines.

Tender Swapping (Part 1) - A Game for Prototype Modelers - Basics of SP Tender Classes

Tender Swapping (Part 2) "Tender Migration" Between Shops - A tender project

OMM Pre-Production Sample Photos

Prices are still TBD, but in the next few weeks I hope to have more info on what we can expect the production pricing to be. - Sept 22, 2021.

Overview of Cylinder Choices

This collage photo is a nice way to see the differences and compare the four different cylinder options.

OMM #4010 - Cylinder, no cover, non-bypass

Original 4010 pre-production sample 2018.

See 4013 comments for status. - Sept 2021.

OMM #4011 - Cylinder, cover, non-bypass

Original 4011 pre-production sample 2018.

See 4013 comments for status. - Sept 2021.

OMM #4013 - Cylinder, cover, non-bypass

The cylinder designs are being updated with some changes for improved 3d printing for volume.  This includes splitting the cylinder into a front and rear section.  the front section will have most of the mass, the rear part being basically a rear cover plate.

Sept 22, 2021 - The 4013 with split print version getting close to production. Waiting on 4012 rods sample to be test fitted before committing to production.

Front of "split" two-piece 4013 pre-production - July 2021

Glued up 4013 "Split" pre-production sample - July 2021

Original 4013 pre-production test part 2018.

OMM #4014 - Cylinder, cover, non-bypass

4014 Cylinder pre-production 2018.

See update on 4013 for newest news.

OMM #4012 - Rods, Yoke, & Crosshead - Cast White Brass

Prototype 4012 parts 2018.

Update Sept 22, 2021 - Pre-production parts should be at foundry now.  Once they're confirmed good, production run will start and foundry will cast parts.

OMM #4015 - Replacement Domes & Boiler Patch - MSRP $24.95/set

Update 2022-12-31: Instructions for 4015 Domes are available for download and printing.  The majority of our reservations for 4015 invoices have been sent out and the paid ones are going to be shipping in the first week of January 2023. - Enjoy!

Update 2022-10-02: Production parts have actually arrived now.  MSRP is set at $24.95/set.  This is the photo of the first 6 pieces and production will be delivered in lots over the next couple weeks to fulfill the reservations.

First 6 production prints of OMM 4015 Domes. $24.95/set

Update 2022-08-07: The OMM 4015 parts are now in production at the 3d printer.  I should have an update for everyone soon with the firm MSRM price for them in the next week or so.

4015 dome set, updated Sept 22, 2021

We're hoping to do a couple of minor changes to the 4015 set and get them into production for everyone!

4015 - Production Version - 2022-05-18

Boiler band added to boiler patch.

The newest version of the domes have been ordered into production.

OMM #4017 - SP 90-R-7 "Narrow" Bunker Conversion part

Currently awaiting slight revisions to improve 3d printing and cost to produce.  Note 4018 will NOT have the curved slope-sheet at the rear of the bunker.

Renderings of 4017 and 4018

3d CAD model of 4017 to be 3d printed.

Test fitting of 4017 to Bachmann USRA tender - July 2021

July 2021 - Wildfire Evac caused me to set this project aside.  I need to get back to it at finish installing the pre-production bunker into the tender body with glue and see how much putty work is required.  Adjustments will be made to minimize putty and body work to the top of the tender deck.

Minor revisions needed to reduce production material and cost. - Sept 22, 2021.

OMM #4018 - SSW-style Tender Bunker (not used on C-8/9/10 class)

Pre-production print of 4018 with primer coat - July 2021

See pre-production notes on 4017. - Sept 22, 2021

Renderings of 4017 and 4018

Note 4018 will NOT have the curved slope-sheet at the rear of the bunker.

OMM #4019 - SP C-8/9/10 Pilot Steps and Pilot Brace - Brass

Waiting for pre-production tooling to be made. - Sept 22, 2021. 

Render of single Pilot Step (pair)

Pilot-Boiler Braces (pair)

Production sprue for multiple 4019 sets to be cast in brass.

In Dec 2022, I talked with my manufacturer and we decided to upgrade the 4019 set to include brass steps for mounting under the smokebox-side running boards too.  This will make the "Common Standard" look complete as far as replacing the Bachmann Pilot-running board ladder goes.  This should be a standard part for any UP/SP/etc engine built to the standard without ladders.


I'll be trying to keep this page updated with any new parts OwlMtModels comes up with for the Bachmann 2-8-0 conversions.  Thank you all for your continued patience with this project through all the delays of the last 3 years!

Jason Hill

P.S. Photo Gallery of Random Pre-production Model Photos.

Photo of disassembled 2-8-0, reassembling the boiler to the frame

SP 3459 with 100-C-3+ tender and OMM cylinder parts (note 3459 did not have C-8/9/10 cylinders!)

3459 model with painted pre-production 4013 and 4012 parts - circa 2018

I hope everyone has enjoyed these older photos from behind the scenes.  I hope to film a video on installing these conversion parts on a Bachmann 2-8-0 when I get the full production parts.


  1. Any update on the replacement domes and boiler patch kit #4015??
    I would like to find out pricing and availability.

  2. Any update on the replacement domes and boiler patch kit #4015??
    I would like to find out pricing and availability.
    Chris Howard, Pell City, AL

    1. please email Sales at OwlMtModels (dot) com for progress updates and reservation status on the 2-8-0 conversion parts.


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