New Toy: Samhongsa NP A3

[delamaize]

Hey everyone, I finally pulled the trigger and bought me a brass steam locomotive. I've been watching a few different NP A class Northerns for a while. in the last few weeks, a few popped up on Ebay, for decent prices. I decided to blow my next few months of train budget, and pull the trigger on one of the factory painted A3s. I'm at work, so I have not had a chance to test run it, but here is a few pictures.

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For our brass Gurus, I have a few questions:
What do I need to know about this locomotive? Like prevenitive maintnance, Known issues, Recomended modifications, Etc.
I'm going to put a decoder in, any precautions, or oddies to look for during the install?
Minimum radius? My current home layout isn't super narrow corners, but it ain't 24" either.
Do's and Don'ts for this locomotive, or brass locos in general? This is my first.

I'm excited to have this loco, and I'm excited to get it with my A4 build and get some picture.

[spookshow]

They have the typical problems associated with the old "stiff wire on drawbar" tender current transfer scheme. Address that and you'll have a fine running steamer indeed.

http://spookshow.net/loco/ola2.html

-Mark

[Ed Kapuscinski]

Oh man, that's a pretty engine. I love how the NP's steam all had a "classic" look, even the very modern things like this.

Good get!

[peteski]

Interesting to see that both #2 and #3 drivers appear to be geared. In my experience, usually only a single axle is geared with others driven by siderods.

[wm3798]

I guess the one thing I can give you fair warning about is the brass main drive gear should be inspected and lubed before you run it for too long.

It's a bit of a pain to get to, you pretty much have to disassemble the motor mount to get to it, but once given a decent drop of heavy gear oil, it should run nicely for a long time.

It's hard to modify the pick up scheme, so you're going to have engine on one side and tender for the other, but you can add a micro plug to establish the connection between the engine and tender so you have a more secure connection.

Lee

[Rasputen]

Depending on the type of turnouts you have, you may need to set the locomotive wheel gauge to the maximum limit of the NMRA gauge, so there is zero daylight between the outer edge of the gauge and the wheel flanges.  Then, re-check the minimum radius operation and check for shorting.  After re-gauging the wheels, you will sometimes need to limit the side-to-side travel of the drivers to prevent binding or shorting.  I can't tell how the left hand brake shoes are connected, but if they are metal you may need to adjust them after re-gauging the drivers to prevent shorting.  I would also check the pilot truck and its wheels for clearance to the cylinders on the left side, the pilot, and the coupler screw if it is metal.  I would also consider modifying the tender trucks and make them pick up power from both rails.  If this locomotive uses a piece of flexible tubing as the motor coupling, make sure it has a nice tight fit and does not slip.

[u18b]

My number 1 rule/advice:    Don't drop it.   

Rule number 2:  take of rings when working on it.  Rings can scratch paint.

If a loco is totally new to you, use your cell phone as you go along to take photos.  I always do this on a new loco.

[Point353]

They have the typical problems associated with the old "stiff wire on drawbar" tender current transfer scheme. Address that and you'll have a fine running steamer indeed.

http://spookshow.net/loco/ola2.html

-Mark

Before you connect the tender to the loco, are you pushing the contact spring wire across to the other side the holes in the loco's drawbar?
This puts more tension on the wire and results in better contact than if you simply connect the tender with the wire in its "resting" position.

[robert3985]

I've cleaned up and repaired a few of these for friends and customers.  They run well, but the main problems that have come across my bench are (1) - the screw and drawbar assembly coming loose or breaking and (2) - the tender trucks corroding very badly.

I've had to machine insulative washers out of Delrin that fix the broken drawbar, which inevitably loses parts when it breaks or works loose.

Photo (1) - Delrin insulative washer being machined on my lathe: 


The trucks are pretty easy to clean up with a small wire brush and a soak in distilled water with some baking soda in it...then rinse, dry, de-grease and re-paint.

Photo (2) - Corroded Oriental Limited NP A3 Tender Truck Sideframe:


Photo (3) - Thick Corrosion Crud from Oriental Limited NP A3 Tender Truck Sideframe:


These seem to be pretty common problems with this particular model, but yours look to be in excellent condition and un-corroded.  This is good, and the engines I've test run, run excellently!

Have FuN!!

Cheerio!
Bob Gilmore

[peteski]

Before you connect the tender to the loco, are you pushing the contact spring wire across to the other side the holes in the loco's drawbar?
This puts more tension on the wire and results in better contact than if you simply connect the tender with the wire in its "resting" position.

Yes, that is a good method.

In one of the locos I  serviced I reworked the drawbar to have a double wiper.



In my experience the drawbar is not really a problematic contact area.  Main thing to address for improving electric pickup would be to add all-wheel pickup in the tender (sine it is pretty much impossible to do that in the loco.

[Ed Kapuscinski]

A one wiper is often cause for note, but in this case, that double wiper is pretty slick.

[peteski]

A one wiper is often cause for note, but in this case, that double wiper is pretty slick.

Yes, I figured it wouldn't hurt. But also remember that even with one wiper pressing against the post, the opposite side is also pressing against the drawbar creating 2 points of contact.

[x600]

Don't worry, Mike, I'll spot you some lunch money at the next show. 

Greg O.