Brass Steam Loco Help

Model Railroader General Discussion (Model Railroader)
1

Recently I purchased my first brass loco. It is a CNR Hudson manufactured by Samhongsa in 1978.

While it is a very nice looking loco with rare factory paint, its running quality leaves a lot to be desired.

It runs fairly well in reverse but has a hesitation going forward with each revolution of the drivers.

I gave it a light lube and checked the drive axle gear which seems ok. I also cleaned the wheels. I have been running it back and forth on my workbench as my layout is DCC. It is running somewhat better now.

Perhaps someone here can give me some guidance as to why it runs fairly well in reverse but not the other direction. I’m thinking it could be the gearbox is gummed up.

I’m aware that Samhongsa locos of this vintage don’t have a reputation for great running, but if you want a CN Hudson they are pretty much the only option. Yes I’m aware that Hobbycraft Canada did get BLI to do a run of them about 2005 but just try to find one. If you do the price will be very high.

Anyway thanks in advance for any suggestions.

CN Charlie

2

That would be my first thought as well. Another thought would be to disconnect the motor, and try rolling it on a straight piece of track to see if there’s a bind in the drivers. If there is indeed a bind in the drivers, start disassembling the rods until you can isolate the bind.

3

There should be a gear cover held on by two screws under the frame. Remove that and clean out the old grease and lubricate with two drops of clean oil.

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If that does not fix it, remove the boiler and the motor and see it it rolls freely by hand.

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Also inspect for any dust build up inside the gears.

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-Kevin

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4

If nothing is bent or cracked inside, it might be the quartering. You’d think the bind would work both ways, but perhaps not.

5

One of the best diagnostic tools I have for locomotive “tuning” is a set of these roller stands:

IMG_6625 by Edmund, on Flickr

I connect a DC supply directly to the motor and allow the drivers to turn at various speeds.

https://www.walthers.com/display-test-stand-rollers-e-z-riders-tm-rolling-w-ball-bearings-for-powered-axles-pkg-4

This allows me to “poke around” and look for binding, stiff springs or thrust washers worn or out of place. Sometimes I have diesel drive trains that have a “squeak” or a rubbing sound that I can’t locate. These stands allow me to try to pin-point the source of the friction.

In your case of running well in reverse but not forward, you might have to look at the condition and positions of thrust washers in the input shaft of the grarbox mounted to the driver.

If the locomotive has spent a majority of its life running forward, that will put a lot of friction (wear) on the rearward set of thrust washers. This also has the effect of mis-aligning the worm gear to the spur gear. Does your loco have an actual gearbox or is it open gear/worm?

This can also transfer the thrust to the motor shaft and if the thrust bearings in the motor shaft are worn you will get increased friction, thus current draw.

Using a DC power source with an amperage readout can help so you can witness the current draw while you look for binding or friction:

Meter-A by Edmund, on Flickr

Some

6

Thanks for the advice.

I did remove the cover on the axle gear and saw that the nylon gear looked in good shape, possibly a little dry so I put a small amount of labelle lube on it.

Ed, I see that there are 2 screws on the back of the cab and I assume that there is a long one under the pilot truck. If I remove these will the boiler, cab and pilot just come off in one piece? I have taken the ‘boilers’ off of plastic locos, e.g. replacing a chuff sensor on a BLI mikado, but have no experience with brass. With plastic, the pilot usually stays with the chassis. I don’t want to damage anything.

I will look at getting a set of rollers. I have considered doing so before.

By the way the engine does smooth out going forward at a high throttle setting.

CN Charlie

7

Charlie,

I’ll 2nd Ed’s suggestion on the roller bearings. They’re also come in pretty handy for breaking-in your locomotives. I would also suggest purchasing an additional set to support the wheels of the tender and the locomotive trucks.

I don’t know how much that brass locomotive has been run but a good break-in period after the cleaning/re-lubing might help smooth out some of those issues of yours.

Tom

8

I recall stumbling across a discount at one of the online sellers (I forget which) but I found a set of four at around $50 after an additional discount. I bought two sets as sometimes, as Tom mentions, four just isn’t enough.

Märklin makes one, a bit pricey; Bachrus another (may be unobtanium) and IIRC MicroMark has a model.

https://www.micromark.com/HO-On30-Locomotive-Rollers-Assembled-Set-of-4

Personally, I like the versatility and quality of the Bachmann ones. The cost seems dear but with four micro-bearings on each one I can see why.

https://www.factorydirecttrains.com/bachmann42901hoon30ezriderswballbear.aspx

Good Luck, Ed

9

That locomotive, owned by someone I didn’t know at the time, was the first brass locomotive that I ever painted for someone other than myself.

Almost 40 years later, we’re still the best of friends, and he was here today to pick up another paint job, this time a Walthers tugboat.

When I took the Hudson home, it ran pretty-much as you described yours, and I knew immediately that it would have to be repaired before I painted it. Not being overly familiar, at that time, with brass models, it took some time to sort out the areas which were causing problems.

Most of them (perhaps all, as it was some time ago) involved interference between the drivers and siderods, the siderods and themselves, and the siderods and valve gear, and the valve gear itself.

The siderods intermittently contacted the counterweights on the drivers, and also contacted other members of the side rods - almost everything that moved on the sides of that locomotive was hitting something else.

Problems in the valve gear were solved with some judicious bending of various parts, as, at that time, I didn’t want to drill out the rivets in order to add spacers. Nowadays, I’d have replacement rivets on-hand and have also learned to make my own, for areas where the commercially-available ones might be too large.

Almost all of the drive rods were removed (make diagrams as you disassemble brass locos as assembly diagrams and exploded views are not included with such models). I simply removed the screws in order to add spacer washers, which I just happened to have on hand for a project I was doing for my

10

Wayne, thanks for the info. I m afraid that level of work is beyond my expertise. I will look more closely at the side rods but now it runs quite well in reverse and somewhat better forward. It has a factory headlight that does flicker so I will try cleaning the drive wheels again.

Wish I was a little closer to you. I live in Winnipeg.

CN Charlie

11

I think that’s only about 1500 miles from here - almost like next door, eh?

Wayne

12

I looked closely at the driverods and all appear straight. I can’t detect any hitting something when it runs very slowly in reverse. When going forward it doesn’t lurch as much as before and again I can’t detect any clicking noise or evidence of a rod hitting.

I cleaned the wheels again and checked the axle gear by taking off the cover. The gear is quite clean and has a light layer of oil on it so I think all is good there.

Wayne, can you give me any advice on removing the shell. I see the 2 small screws at the back of the cab. I assume there is a long one under the pilot truck. Does the pilot come off with the boiler? I see there is a plastic tube from the water pump that goes through the frame above the trailing truck so I assume the pump is attached under the running board. I want to check the gears. I will have to watch out to see how the headlight is wired.

The seller said the engine had little to no use as there isn’t any wear on the drivers. The seller is a large dealer in the U.S. I think the loco was used a little as it has a Kadee on the tender.

I ran it back and forth for about 10 minutes late last night and it is running better. Reverse is quite good and forward is improving. The lurching is less than before.

Again thanks for the advice,

CN Charlie

13

It’s been a long time since I worked on that locomotive, but on most brass models, the screw which holds the lead truck in place also holds the smokebox end of the loco to the cylinder saddle. The loco’s pilot is usally soldered to the front end of the frame - when you remove the two screws at the rear and the one holding the lead truck and front end together, the superstructure should lift right off, leaving you with the frame, drivers and trailing truck, along with the motor.

There’ll also likely be a pair of wires for the headlight, and it would be unusual if they’re plug-connected, one reason why I disliked adding lights to locomotives which I did for others. I gave up on lighting my own years ago, but there are lots of sources nowadays for mini-plugs, which would allow for complete (and easy) separation of the superstructure from the running gear.

It sounds as if you’re making progress with the running gear, so maybe yours is from a later period of the production. Looking back on what I did to get the other one running smoothly, it was pretty basic, but I was definitely in uncharted waters at that time.

Wayne

14

I tried running the loco without the tender but it will only run with the tender attached?

Many years ago I had a Penn Line consolidaion and it ran wihout the tender.

I thought on DC the loco would run less tender or am I missing someihing?

CN Charlie

15

The loco picks up the current only on one side, the tender the other side, so you need to have the tender coupled to the loco.

My 1974 vintage HOn3 WMC D&RGW T-12 had a slight glitch in her gitalong when running forward. It took me 45 years to figure out why, as the quartering was OK and the side rods were straight. I finally detected two reasons:

  • The frame was slightly bent.
  • The worm gear “shunted” in the gear box.

I carefully straightened the frame as well as the worm gear bearing - that did the trick.

16

Ulrich has explained how most locos work - brass ones for sure, and the older cast metal ones, too.
However, many, or perhaps most more-recently offered steam locomotives have all-wheel pick-up. They generally still need to be connected to their tenders, though, either if they’re equipped with DCC or if they have a multi-function circuit board in the tender that runs the motor and lighting. In these, the loco picks-up power, as does the tender, but the power from the locomotive is sent to the circuit board or decoder, then to the loco’s motor.

Because I run DC and don’t use lights, most of my steam locomotives can run without their tender for testing or maintenance purposes, although in normal operation, tender pick-ups are also useful to ensure uninterrupted power to the motor.

For brass steam locos and older cast metal ones, their reliable operation can be enhanced by adding all-wheel pick-up to both the locomotive and the tender, using wipers on all wheels, as on this Bowser PRR A5, which I built for a friend.

This one is DCC equipped, but the wheel wipers will work for it or for DC. I add them on the loco’s drivers…

…and to the tender’s wheels, too…

Obviously, for the DCC-equipped loco, all wipers are wired to the decoder in the tender, using plugs, then from the decoder to the motor and lights, using plugs.

For a DC controlled locomotive, you can wire the drivers’ wipers directly to the motor, then add a pair of wires from the tender, using a plug, like the one shown belo

17

Thanks Ulrich and Wayne for the info. I understand now.

Wayne, that second photo of the Hudson banjo frame shows something that is causing me concern when lifting off the boiler, and that is the tube that goes from the water pump ( or is it injector?), anyway, that is a piece of plastic tubing and I don’t want to try to remove it from the pump end as it is a friction fit and I think the risk of damage is high if I try to pry it off. Therefore I am thinking it would be better to remove the banjo frame other wise that ‘pipe’ will restrict the ability to pull up to remover the boiler. I also have to contend with the wiring for the headlight. What do you think?

I’ve replaced bronze wipers in a Bachmann light mountain but this is all new territory for me.

Thanks again,

CN Charlie

18

That plastic tube representing a pipe has always bugged me, but I’d have to contact my friend and borrow his locomotive to fully recall the set-up. While I’m at it, I intend to replace it with something better, if possible.

I pulled it out when I did both the repairs and the paint job, and if you want to remove the boiler/cab assembly, you’ll need to do likewise - it’s not very flexible, but it can be removed and re-used.

If you can wait until sometime next week, I’ll see what I can come up with.

Wayne

19

Thanks Wayne, I’m in no rush so will wait until I hear from you.

By the way, I used to travel out your way quite often 25 or so years ago. My employer had dealer stores in Stony Creek and Hamilton that were in financial trouble and I was the guy responsible for our financial exposure. I did enjoy the trips to that area.

CN Charlie

20

I dunno why, but the first thing that springs-to-mind for me would be Colour Your World, although they may have already been gone by that time.

I’m not sure you’d enjoy it that much nowadays. Hamilton is no longer the same city that I grew up in and where I worked.

Wayne