Author Topic: N scale CPR/BCR Royal Hudson build thread  (Read 700 times)

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N scale CPR/BCR Royal Hudson build thread
« on: November 04, 2016, 03:58:10 PM »
Hello all. 

I'm starting this thread to document efforts to scratch build a CPR/BCR Royal Hudson.  This began with a thread on the N scale page to create/gauge interest. That thread is located here:

It's in this thread that we'll discuss the building of the loco and chronically its progress as the project comes together. 

I'll ask that those of you who offered to help on the other thread, show your willingness to help again here so I'm not speaking for you.

My hope is that we can put together a team of interested people who can pool their skills and create an accurate model "kit" for lack of a better term, that we can all build for ourselves, posting progress here.  I say "kit" in quotations because I don't foresee this as an endeavor to create a commercially available kit where a modeler gets all of the parts and instructions, but more of a group effort to create accurate parts, using all technologies available to us, that would would then scratch build the loco with.

As far as funding goes, each modeller will be on their own as far as procuring parts and models, however if the chance exists to save money by buying as a group then we can explore that.  Likewise for things like etching, the hope is that we can band together and share in the deveolpment costs.  It gets really reasonable when divided over several people.

I'm not ready to start this thread off the way I wanted to but I felt it was time to get it going as the original thread is starting to drift into discussion on techniques, parts, etc that really belong here.  My intent was to start the thread with links to drawings on the web, commercially available detail parts, and viable locos to use as a starting point.  I will also photograph the various parts I already have in my collection for people see and evaluate.  I'll do this by editing this first post so that all of the information is in one spot for easy reference.  If anyone else has anything to add to this post then feel free to mention it in a reply so followers see the changes, and I will then add those links to this post to keep everything organized.

Already there has been some discussion about chassis, etched parts, rapid prototyping and versions that people want to see produced.  I'm really liking where this is going and am looking forward to being a part of the project.

For interest sake, and because some members posted some relevant information that will be useful, I'll link to my older posts on this same subject:

Aug 2012:

Oct 2014

The October thread had a lot of good insight and it's my hope that we can attract a lot of those people back here again.

(Looks like I get this bug about this time every two years.)

Thanks for you interest.


Prototype Drawing Links:

coming soon

Prototype photo sites:

Coming soon

Previous known conversions

Custom models aside, I'm aware of two prior ways to model a Royal Hudson. The first was using Miniatures by Eric parts to convert a Con-Cor NYC J3a Hudson. The result was a model that passed for a RH and looked the part but wouldn't be considered accurate by any means, no offence meant to the modellers at that time.  This conversion can be seen in the N-trak "N Scale Steam Locomotive Handbook", page 6.18.  The NYC Hudson was a much longer locomotive (actually its more accurate to say that a RH was a smaller Hudson than most others, being more like your average Pacific).  Also, the RH had a semi-streamlined boiler jacket which made the visible diameter of the boiler appear larger.

The second way to do it was by starting with a DelPrado static model of a RH and mounting it on the same Con-Cor mechanism. I tried this a long time ago and was disappointed. First at what I paid for the DelPrado "model". At the time they were hot on eBay and I'm pretty sure I paid close to $75 US for it, only to find out that it was very toy like and not detailed to my standards. I should have known by the lack of closeup photography. Moving on. I did mount it on a J3a but I didn't like it. I sold the J3a and the DelPrado Hudson is in a baggie in a box some where. An article on this conversion can be seen on p36 of the 2009 Steam Locomotive Information Book Addendum.

Commercially available model parts:

Most of these are MBE parts and some of these parts are still available from MBE but other more important parts are not.  However, as long as the molds are still intact I see no reason why we couldn't get a re-run done, or at least inquire.  I've worked with MBE before and it was a good experience.

Locomotive Parts
*Disclaimer. Parts I'm posting here are what is currently available, or has been available in the past. They may or may not be acurate and may or may not be used on the model.

Smoke box front
This is a MBE part made for the Con-Cor Hudson. It's no longer available and is too small in diameter.

Smoke stack:

MBE made both a stream lined stack and a non steamlined stack.  Neither is on the sight at this time.  I have a streamlined one which looks right to me but it was mentioned in the other thread that it might be not the right size.  This could be due to the fact that it was made to fit the Con-Cor model.  Mine can be measured to confirm.  I do not have one of the non-streamlined stacks



Not quite correct but close

Steam generator

Steam check valve
No longer in the website, photo soon.


MBE used to list the pilot on the website but no longer does.

Trailing truck:

These are side frames only and need to have a truck built around them.   The prototype has a 36" wheel set on the front and a 45" wheel set on the back.  I used a Fox Valley Models 36" metal set for the front and NWSL HOn30 wheels on the back. Part number 37362-4. They have the /64 tread like the N scale wheels and are 24" in HO.  Scaled down to N that is 44.16".  I cut the axles down and reassembled them using styrene tube in the same way a modern N Scale loco has split axles. With the side frames being brass, I found it difficult to modify them to fit the axle points and while my truck looks good and rolls well, it's not perfect and I feel that for this loco to run smoothly, it needs to be near perfect when it comes to anything with wheels.  I'm planning to revisit them and possibly recast my side frames in resin.  Another possibility is to rapid prototype the whole truck and just snap the wheels in.

Valve gear:

This is the gear from the Kato GS4. (Frederick's advised me this part is no longer available. See the FEF notes below)

I was told that it is the correct type but after buying it it's my feeling that it's too large.  We'll confirm with measurements.

It's possible that the valve gear from a Kato Japanese Hudson could be used but parts for these locos are very hard to find.

The Kato FEF valve gear could also be a match. Frederick is investigating this and will report back about measurements and how well they would fit the RH model.


MBE at one time made a complete tender which would have been for one of the coal burning locos. It was a solid white resin casting and was made up of three pieces consisting of the main body, coal bunker, and underframe. I have one and it would need conciderable reworking due to being a solid body. Also the under frame is warped. Being that it's kind of crude, and is unavailable I would think the best choice would be to scratch build or rapid prototype one.

Common wealth tender side frames H1C/D:

These are side frames only and would need to be built into a useable truck.  These could be a candidate for rapid prototyping.  I'm not aware of an off the shelf part that has needle point bearings for pick up.  Perhaps some steam aficionados can weigh in on that.  With rapid prototyping perhaps a truck could be made that accommodate the pick ups and wheels from another needle point bearing equipped truck?

Frederick mentioned that Bachman makes a Commonwealth truck and this jogged my memory about an article in the 2008 NTrak Steam Book Addendum. There is an article on Bachman tenders and indeed their Vanderbilt tender has common wealth trucks with pick ups. This would appear to be the best solution.

Buck-eye tender side frames H1E:

These trucks are from Micro Trains.  They have no electrical pick-up.  Streamlined Back shops makes contacts for them in either wheel wipers :

Or axle wipers:

 ...but it would be using a friction contact which will adversely affect the performance.

These are from the Kato GS4 spare parts section.  They are slightly  larger than the Micro Trains trucks and they have Katos reliable electrical pick up.  I'm not sure if the dimensions are too large for a RH tender.  I'll post some photos and measurements of mine compared to the Micro Trains trucks. Still, if we can make them fit, even if they are a little large, these are the best ready to roll Buckeye trucks around. Update: unfortunately these are out of stock at Kato as of Nov 8, 2016.

Here are the Microtrains and Kato trucks together for size comparison. Notice how much larger the Kato trucks are. It's my feeling that they are too large for the RH but I'll confirm with measurements soon.

In the same article I referred to above, it's mentioned that the Bachmann Auxilliary Water Tender has Buckeye trucks. I havn't seen them but I'm going to try to get some so I can evaluate them.  I'm not even sure if they have electrical
Pick up.  Spookshow has a pretty comprehensive write up on them here:
 It's my guess that the trucks on the Aux Water Tender are one of these and likely don't have electrical pick up. I'm seeking more info on these.

Tender water hatch:

Oil hatch:

Buffer Plate:

Possible chassis to base the model on:

Model Power Pacific

When I started this scheme about 10 years ago I had planned to base my model on a Model Power Pacific, and since I own one, I still plan to use it.  (Edit: I just bought a Kato C55 and I'm pretty excited about it. The MP Pacific may get shelved). It's driver size and spacing measures out very closely to a RH and while out of the box it has some issues, it can be modified to be a very good runner and puller.  I'm linking here to a review on the Spookshow website. there are two releases, 2002 and 2015.  He discusses both of them in detail and also changes that can be made to bring the running quality up to a higher level of performance.

The Coles notes of these modifications are add traction tires and swap the tender for an all wheel pickup design with needle point axle contacts.  My Model is the original run that does not have traction tires. MRC no longer supplies parts for the older MP locos. To get some traction tire equipped drivers, they referred me to a fellow who bought all of the parts. He has not replied to my email and so at this point I don't see it being possible to upgrade my model. If you are getting a MP Pacific MAKE SURE IT HAS TRACTION TIRES.

The most notable INACCURACIES in this chassis are:

1. First, and most obviously, it's a pacific and so we need a rear truck.

2. Wheel spacing: It's not perfect but it's very close.

 From Greg Kennelly in my 2014 thead:

"Lead truck:  MP  32 1/2" wheels, 7'-6" wheelbase; RH 33" wheels, 7'-2" wheelbase

Centreline of cylinders - lead driver centre:  MP  8'-9 5/8"; RH 8'-2"

Driver diameter: MP 71 1/4"; RH 75"  (MP over flanges = 80")

Driver wheelbase: MP 13'-10 3/4"; RH 13'-2""

3. Valve gear: More detail to come, but I can say right now that it's wrong.

Kato x-6-x

When I brought this up before someone mentioned the possibility of using a Kato Japanese chassis.  A C57 was mentioned in my 2014 post but I looked it up and it doesn't have the spoked drivers we need.  However the C55 Pacific does. The C55 has 74.3" drivers, according to Sppokshow, which is a close a close enough match for the RH 75" drivers. At a glance the spacing looks as close as we can expect too.

Spookshow gives this model an A grade. It has a modern split frame design, the motor is in the chassis and not the shell, electrical pick up is the more modern and efficient bearing block design, no wipers, and it has a traction tire.  They are readily available.  Also the valve gear looks close enough to me that I wouldn't modify any of the moving parts on my loco.  As this is my dream loco, and I want it to actually run, I totally get that the chassis is the single most important thing.  I have ordered a Kato C55 and look forward to evaluating it.


Black Cat makes decals for CPR modelers.

BCR modelers will have to use a combination of these and some custom made additions>
« Last Edit: November 08, 2016, 03:27:08 PM by craigolio1 »


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Re: N scale CPR/BCR Royal Hudson build thread
« Reply #1 on: November 06, 2016, 09:23:27 AM »
Just a note about the valve gear, the GS4 valve gear set is not currently available. That said, the FEF3 set is, and also has the under-slung crosshead guide. Haven't checked the size yet versus RH drawings, but I do have some on order, so as soon as they come in I can check. As for the C55, the crosshead guide is mounted outside the support, while the RH is mounted inside:

I'm thinking the FEF3/GS4 guides will be closer to the RH:

Also, the Bachmann commonwealth tender trucks are very close in size to the MBE trucks (the Bmann trucks are just a bit smaller, I'll measure them later), they don't require that fiddly assembly process, and they already have low friction electric pick-ups. I plan on using those for the H1c/d.

kind regards,


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Re: N scale CPR/BCR Royal Hudson build thread
« Reply #2 on: November 06, 2016, 12:28:24 PM »
Good info Fredrick.

I compared photos of the C55 and the RH and could tell there was a difference in the valve gear. I don't know much about it so I couldn't figure out just what it was.

I've ordered a C55 as the drivers are spoked, and are the correct size. I'll do a full comparison of its measurements when it arrives.

I have the GS4 valve gear and holding it up to the MP Pacific, which is a few mm longer than a RH would be, it looks too big to look right.

I plan to take photos of it soon and post them here.


Edit: and thanks for posting those sweet close up photos and tender info. When I have a chance I'll add them to the original post up top.
« Last Edit: November 06, 2016, 04:33:39 PM by craigolio1 »


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Re: N scale CPR/BCR Royal Hudson build thread
« Reply #3 on: November 08, 2016, 02:43:38 AM »
In the previously linked photos, the main differences I see between the GS-4 valve gear and the RH are:

1.  The shape of the Walschaerts link is different (the RH has a relatively long extension at the lower end where the eccentric rod connects)

2.  The combination lever on the RH is shorter

3.  The union link (between the combination lever and the crosshead) on the RH connects to the crosshead at the same point as the main rod ; on the GS-4 it connects to an extension from the lower edge of the crosshead.



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Re: N scale CPR/BCR Royal Hudson build thread
« Reply #4 on: November 08, 2016, 03:18:35 AM »
Greg your knowledge of these things always blows me away. I don't know what any of those things are, haha. Except for the cross head. I know what that is.

When I compared the GS 4 valve gear to that on the MP Pacific, what was immediately noticeable was that it was huge. The cylinders were twice the size. Even if they were a perfect match for the RH they would look like two giant saddle bags. 

On my own model, I'm ok with the valve gear being close. For me it's the mode as a whole that makes it. I can over look a detail like that, as long as it's close. I know for someone who is all about steam that may be a deal breaker but I'm more interested in it running well and messing with those tiny watch like moving parts scares me.

Thanks for your input and please feel free to contribute any time. I know how vast your knowledge is. 



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Re: N scale CPR/BCR Royal Hudson build thread
« Reply #5 on: December 23, 2016, 03:04:26 PM »
Hello all,

I too am planning to build at least a couple H1a/cs and an H1e. I have the actual plan and will turn the boiler (either over the winter or during my sabbatical in the summer) during 2017. Keep me posted and I will do the same!

Kind regards,
Michael Livingston 
Michael Livingston
Modeling southern Ontario in N scale

Better to remain silent and be thought a fool, than to speak out and remove all doubt. ~ Abraham Lincoln.


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Re: N scale CPR/BCR Royal Hudson build thread
« Reply #6 on: December 27, 2016, 08:13:21 PM »
Thanks for your interest. It doesn't look like much is happening here but in the back ground the wheels are turning slowly. If you start work on something please post it here. This thread is by no meant to only cover my own efforts.



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Re: N scale CPR/BCR Royal Hudson build thread
« Reply #7 on: January 08, 2017, 05:01:25 PM »
I joined up on here solely because you have made an excellent rendition on how to assemble the MbE trailing truck side frames. I am currently in the process of making a Con-Cor 2-10-2 into a Texas&Pacific 2-10-4 with the same castings and had been wondering how to assemble them. I've got brass strip and inspiration from you on doing that now. Would by chance have an extra HOn30 wheelset available for sale?


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Re: N scale CPR/BCR Royal Hudson build thread
« Reply #8 on: January 10, 2017, 11:48:03 PM »
No im sorry I don't. Are they no longer available from NWSL?

My method needs refinement. Maybe a jig or something as whenit rolls it has a bit of a wobble and isn't free rolling like say a Microtrains freight car truck. Being that steam locos can be weak pullers I don't want my modifications to weaken them even more.

On my next attempt I think I would take a page from a couple of resin loco kits I've built since I made this truck. They had drive wheels secured in place with etched brass sides that created a sort of bearing. The side frames were glued to that and not structural.

I would plan to do the same on my second attempt. I would make a simple brass rectangle that I could make two exact copies of with holes drilled for the axle points. Then solder to those some angle. The angle would be screwed into two plastic cross pieces that would over lap and be secured to each other with two screws. This would allow adjustment inward and outward to get the exact correct friction on the brass sides.

Once that's perfect I would hollow out the side frames to make room for the axle points and glue or solder them on, instead of them being structural as they are now.