M420

[mandealco]

I can't seem to leave this thing alone.  I had a closer look at the fit of the shell on the Atlas/Kato U-25B chassis.  Although the shell fits straight on, there could be minor trimming of the metal chassis to allow the end platforms and steps to fit correctly.   I may have a better look at this at the weekend, if time permits.

The more I look at the shell, the more I like it.  The early Briggs Alcos are good, but this is a leap ahead.  Anyone considering purchasing this kit should download the instruction booklet to see what's involved.  They are very thorough and should make the job of assembling the model as easy as it can get. 

Cheers
Steve

[BCR 570]

Hi Steve:

Be sure to keep us update on your progress - I will be looking forward to seeing what you can do with it.  I am in M-630 mode at present so mine will have to wait unil their bigger brothers are done.

Tim

[Hyperion]

I mentioned this on a Weekend Photo thread a couple weeks back, but I absolutely loved the kit that I got.  I would, literally, buy all my models in this manner if it were possible.  The detail is great, the it goes together perfectly, and you get every option under the sun all in one pack.

My only issue, and I need to spend a little more time determining just how big a deal it will be to fix, is that the models seems to bulge very slightly when I put it onto the chassis.  That is of course after removing all the offending friction nubs off of the chassis.  I only noticed right as I was finishing up the last time I messd with it, and it appeared extremely small.  The bigger issue was the requirement to remove it from the chassis since it was kinda 'forced' just slightly onto it.

Hopefully I can just make a couple passes over a large file with the chassis and call it a day.

Either way, as I said, I love the thing and I'd buy every locomotive in that manner if it were possible.  Presuming this is a money-making enterprise for him, this really opens up the window to getting any model you want in N scale, and at a very high quality too.

[lock4244]

Couldn't agree more, Mark. Jeff did a fantastic job with the M420 kit, and it seemed to me that it was almost easy to build, and for me that says a lot since this really is the first actual modeling I've done. My downfall so far is the handrails... have bent one to shape, but I have learned quickly that it is my least favorite part of the build.

[mandealco]

Hi Guys
Here's the update on my use of the Atlas-Kato U-25B chassis:

The U-25B option looked great, but there are some fish hooks when you start to make it work. 

The Pro's:
No need to use wires for the electrical pick up.
Kato built chassis.
Shell fits with little effort, just a little filing in the corners for the end platforms.

The Con's:
The truck mounting requires 4 small sections of the side sill to be left in place.
This requires the Briggs kit, underframe sections to be cut to fit.  (something I haven't done yet.)
If I make another, I will again use the U-25B.

I would normally get my son in the RNZAF to mill the frame for me.  As I have nothing between an angle grinder and needle files, this was largely done with the grinder.



This is what the shell and fuel tank look like in place.  The fuel tank is a push on fit, so far.  There is room for the underframe detail, but I'll have to set up the correct height of the shell first.  Then the underframe parts will need to be cut and pasted so to speak.  Should work fine.



For anyone wanting to do the P&W (M-420R) version, there isn't much room for the type "B" (I hear what you're saying Jerry) truck to swivel as the brake rigging is a tight fit on the longer tank on the CN version.  The M-420R uses a smaller tank than the CN one, but larger than the BC Rail version.

I will leave the project here for now.  Have to complete my C-430, C-636P and SSB-1200 first.  My first project this week is to keep my job through a necessary restructure.  Not looking too good right now.

Cheers
Steve

[daniel_leavitt2000]

Are you sure you need to modify the Briggs shell? that ride height look about right to me. These ran very high on their frame.

Too bad the U25 never came with floading bolster trucks. I would have used that.

[mandealco]

Hi Daniel
The truck sideframes that come with the kit, should fit the Atlas-Kato truck, in much the same way as they would on the FB-2 trucks on the B23/30-7, that the kit was designed for.

Cheers
Steve

[Ian MacMillan]

Very nice Steve... just the kick in the pants need to order my two and them started.

[BCR 570]

Hi Steve:

How does the U25B chassis work out in terms of truck centre spacing and truck wheelbase?

Am I right in thinking that this chassis was very similar to the Atlas/Kato RS-3 and RS-11 chassis?  If so I should probably consider using it as it would be advantageous to have my M-420s run well with my RS-3s, RS-10s and RS-18s.  Of course I would want to see how you make out with yours first, however, so how about shelving those other projects and pushing ahead with this one . . . 

Cheers,

Tim
 

[BCR 570]

One more thing, can you tell if the U25B chassis can give up enough material at the forward end of the fuel tank to accept the samller BCR fuel tank?

Tim

[mandealco]

Hi Tim
The U-25B truck centres are fine, they line up perfectly with the jacking pads.  The chassis is a refinement of the older RS-3/11, and runs better than the older ones.  Not sure about speed matching, but probably okay as the gearing should be identical, though motor speed could be different.

I can be tempted to put aside other projects (especially the EMD one), till I at least get the frame sorted and anything else that could differ from the intended chassis.

Cheers
Steve

[mandealco]

Doh!  I will have to look at the chassis to see if it'll work with the BCR fuel tank.  Is the rear end of it set as far back as the CN version, or is it more centred.  I will check it out tonight.
Cheers
Steve

[BCR 570]

Steve:

Thank you for your replies.  Yes, the fuel tank on hte BCR units is set back to the rear with a big space in front.

Tim

[johnh35]

Not sure about speed matching, but probably okay as the gearing should be identical, though motor speed could be different.

Cheers
Steve

Not sure if it is true or not, but I seem to recall people swapping the U25B trucks into the RS3 due to lower gearing.

[mandealco]

Tim
The news doesn't look good for the BCR fuel tank on the U-25B chassis.  The Kato motor sits slightly lower, so there is less meat in the frame round the motor.  I suspect if you remove enough metal from the tank area to create more daylight under the frame, it would be weakened considerably.  Even looking at reversing the ends, the outcome would be the same. 

My conclusion is, that the fuel tank area on the U-25B, in a BC Rail unit, would be a bit of a compromise.  From most angles, it would look fine, but from low down, any metal left to maintain some strength in the chassis, would be quite noticeable. 

Sorry I hadn't thought about that earlier, I guess my focus was on a CN unit, for which the U-25B seems to work.  A P&W M-420R would also work, but the tank may have to be a little longer to hide the metal frame, but not as long as the CN version.

I have some photos I can send you if you want to see what I mean.

Cheers
Steve