Author Topic: Powered Chassis  (Read 1866 times)

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Jim Costello

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Powered Chassis
« on: March 23, 2021, 07:37:44 AM »
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I  am considering modelling a New Haven MU 'Washboard' sometime in the future. Other than the Brass models made years ago and very limited I doubt that we will ever see a commercial product. I would  like the model I do will be as close to scale as practicable .( My other NH modellers will soon tell me where I went wrong! )
 The body shell is not a issue at the moment.  I would like to have both  powered units as well as trailers.
My concern is for a powered unit. The Kato  RDC would be ideal..correct wheelbase of 59'6" centres but truck wheelbase is 8'6" compared to 8'0" prototype and 33" wheels against 36" . I realise that the wheelbase is less than 0.040" longer, so if I could fit 36" wheels then with new truck side frames the difference may be overlooked. I will have to get new truck side frames made for both the powered unit and the trailers and 36" wheels are available for trailers.
Do I go with this or should I consider something closer to prototype. I am thinking maybe a stretched switcher mechanism...correct 8'0" truck wheelbase and 40" wheels turned to 36"....or could the drive wheels be replaced with a 36" passenger car wheel ( from the same manufacturer possible using Atlas or Kato parts)

What have forum members done in similar circumstances in your modelling efforts?

Jim
Modelling the NH down under
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randgust

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Re: Powered Chassis
« Reply #1 on: March 23, 2021, 08:32:59 AM »
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I'd suggest there's another tradeoff here.

You can build an accurate model - but also consider what you plan to do with it.   If you have a layout where this is a 'runner'; part of the operating plan and not just a display model, I'd lean heavily toward the Kato chassis for performance and more importantly, availability of parts, and in the future, junkers and spares to keep it going.   

There may be a Tomytec chassis that could be adapted and hacked - they are pretty easy to modify and either lengthen or shorten to a precise wheelbase, and you can really put about any motor in there you want including an Atlas slow-speed with flywheels instead of the stock Tomytec motor.  But Tomytec has a nasty habit of running a chassis for a while and then either updating it or replacing it to the point where some parts are either obsolete or unavailable.

The chart that is here on Railwire is excellent for basic dimensions - but also look at the Plaza Japan ebay store as they typically scan the drawing of the chassis so you can determine truck wheelbase, sideframes, pickup method, etc.

And, shipping from overseas (Japan) has gone nuts in case you haven't noticed.  I hope that when international air travel picks up again this normalizes, but the prices with shipping are easily double and sometimes triple what they were two years ago.

Lemosteam

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Re: Powered Chassis
« Reply #2 on: March 23, 2021, 09:20:37 AM »
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Jim Costello

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Re: Powered Chassis
« Reply #3 on: March 23, 2021, 07:10:48 PM »
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Thanks for your comments.
I do have a layout and yes the models are intended to run. My thoughts are with the Kato unit also and I have plenty of these in my stash.

I do have the chart on mechanisms that was done several years ago . The closest chassis/truck wheelbase/wheel diameter  is the Greenmax 5517 chassis, but it need to be extended. Truck wheelbase is shown as 8'1" with 35" wheels
and would also be suitable.

I am totally aware of freight costs. We have had a hobby shop since '74 and  airfreight/USPS costs are overboard. WE also do not have surface mail service from the US anymore which adds further to our costs.

Jim

SkipGear

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Re: Powered Chassis
« Reply #4 on: March 23, 2021, 07:57:06 PM »
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I have another option that may or may not work....just spouting ideas. The RDC trucks have the driveshaft low, the NW2 trucks are also the same. If the NW2 trucks are the right wheelbase, they may be useful.
Tony Hines

Jim Costello

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Re: Powered Chassis
« Reply #5 on: March 23, 2021, 08:21:51 PM »
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Thanks Tony, I was not aware of the NW2 drive. I do not have one to check out at the moment and see if it would fit the RDC  chassis.

Any of the switcher models eg SW's, S-2, VO 1000  all have the correct 8'axle spacing and the larger 40" wheel but the chassis would need to be extended.
Will see if i can pick up a NW2 or trucks.

Jim

peteski

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Re: Powered Chassis
« Reply #6 on: March 23, 2021, 08:28:11 PM »
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Thanks Tony, I was not aware of the NW2 drive. I do not have one to check out at the moment and see if it would fit the RDC  chassis.

Any of the switcher models eg SW's, S-2, VO 1000  all have the correct 8'axle spacing and the larger 40" wheel but the chassis would need to be extended.
Will see if i can pick up a NW2 or trucks.

Jim



Funny, we have discussed low-style gearbox trucks here some time ago. Here is a photo of the KATO  NW2 (left) and RDC (right) trucks.
More photos in my gallery: https://www.therailwire.net/forum/index.php?action=gallery;su=user;cat=1269;u=2700
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ncbqguy

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Re: Powered Chassis
« Reply #7 on: March 23, 2021, 08:35:26 PM »
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Parts availability from Kato isn’t all that reliable.   Unless you’re willing to buy compete preowned units the chance of getting parts is nil if they don’t have them from decades ago....and the likelihood of a new run without a re-engineered chassis is slim....which means some parts are gone forever.
You’ll need non-powered units which may also influence your choice.
Charlie Vlk

Jim Costello

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Re: Powered Chassis
« Reply #8 on: March 23, 2021, 08:46:44 PM »
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I don't remember the discussion on the trucks as I suppose it had no bearing on my modelling at the time. Thanks for the photos, it would seem that the NW2 trucks will not fit the RDC chassis easily.
 Trucks for the NW2 are currently available from Kato  but I am aware of parts reliability from manufacturers over time.

Jim

peteski

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Re: Powered Chassis
« Reply #9 on: March 23, 2021, 10:04:08 PM »
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I don't remember the discussion on the trucks as I suppose it had no bearing on my modelling at the time. Thanks for the photos, it would seem that the NW2 trucks will not fit the RDC chassis easily.

I originally posted those photos in this thread. It is somewhat related to what you are looking for.
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Dirk Jan Blikkendaal

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Re: Powered Chassis
« Reply #10 on: March 26, 2021, 03:25:25 AM »
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Jim,

To get back to your question: if its not going to be a display/rivet counter model I would go for the most reliable/available drive. If the RDC has the correct wheelbase I would ignore the 6 inch truck wheelbase difference and even the 3 inch wheel diameter (less the 0,5 mm). You could even have the new sideframes made to the correct 8 feet distance  and given the thickness of these frames now one will see that the axles bearings are (each) about 0,5 mm off when the unit runs on your layout (only when someone picks up the model and looks from 1 foot distance).
Measures are quite relative .... certainly in N scale....... but thats my opinion.
For example the Kato E8/9...... I am working on the ATSF 1 and 10 spot, the rebuilt Amos and Andy. I had a drive figured using Tomix parts..... but the situation changed when I found some parts are not readily available anymore (as Randy already stated), so that solution is out. Then I thought about the Kato drive: readily available, outstanding performance and not expensive. The total wheel base can be modified but the E8/9 truck is even spaced (total wheelbase 14 feet 1 inch prototype) versus uneven spaced 7 feet 6 inch and 6 feet 7 inch (also 14 feet 1 inch total) on the 1 and 10 spot. I decided to take the 0,5 mm off for the middle axle for granted given the consideration above.
But now comes the funny part : you would think the Kato truck would be prototype..... ITS NOT.... 14 feet 1 inch is 26,82 mm  in N scale but the model truck wheelbase is only 26 mm..... NOBOBY ever noticed this on this highly recommended model....... SO FAR FOR WHATS EXACTLY PROTOTYPE...... its what you see/believe/think........ my 2 bits worth....   

All the best, Dirk Blikkendaal
« Last Edit: March 26, 2021, 03:28:06 AM by Dirk Jan Blikkendaal »
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Point353

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Re: Powered Chassis
« Reply #11 on: March 26, 2021, 03:58:50 AM »
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I  am considering modelling a New Haven MU 'Washboard' sometime in the future.
My concern is for a powered unit.
Have you investigated the washboard shell from Island Modelworks and inquired of them how they suggest it might be powered?
http://islandmodelworks.com/N_New_Haven.html


Jim Costello

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Re: Powered Chassis
« Reply #12 on: March 26, 2021, 04:27:45 AM »
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Dirk,

I have come to the same conclusion in using the RDC chassis and fudging the side frames to fit the RDC truck for powered units.
For the trailers I would use the same sideframes fitted to a Kato or similar passenger car truck so that I could getpickup for interior lights etc. The sideframes I  have are of a very poor quality and not fully formed
so I will try and resin cast them and try to get a better master from that.
I have a good quality photo of the actual side frame that could be the basis of a 3D print....(hint..anyone interested ?)

I also agree with your other comments regarding ' other measurements' on models we want to use for other, but similar projects, in trying to build a close scale model.

Jim

Jim Costello

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Re: Powered Chassis
« Reply #13 on: March 26, 2021, 04:36:08 AM »
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Point353,

Yes, I purchased two of the models years ago. I was totally disappointed with the purchase. I understand the N scale products have been discontinued.
The body shell is short, sides warped  the width several scale feet too wide and a RDC falls inside the shell. The trucks are designed  like passenger car trucks, but some of the detail missing
The castings had a lot of air bubbles as well and are cast from a soft material. I believe the photo shows the HO version.

Jim

randgust

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Re: Powered Chassis
« Reply #14 on: March 26, 2021, 11:31:01 AM »
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A few years ago a discussion with my good friend that's a Kato USA guy... I'll offer this up....

'because self-propelled units are so prevalent in Japan, Kato figured the RDC would sell well... and ran a BIG production run.   Anybody want a warehouse full of RDC's?'

I'm not sure where they all ended up, but I interpreted that to mean there was a big stock out there, maybe released, maybe not.   You won't see another production run, but there's a lot of material out there.

They and Atlas tend to order parts as a percentage of production rather than a sales forecast for resale, so your odds of finding parts are often in reverse to the popularity of the model and in relationship to the run.   Conclusion?   You'll see RDC's floating around for years even if there's not another run.   And why finding parts for the 2-8-2 is next to impossible now, way too popular, along with enterprising modelers using trucks and other parts, and GHQ producing conversion kits.

Easier to find frozen turkeys than fresh prime rib.