I have an Athearn BB SW7 which stalls in places where it should not stall. If I just gently push down on the locomotive, it will start up and resume it's route. I have been thinking that this lack of track contact is due to the locomotive being too light. So, I placed it on my postal scale and it weighs in at 7 ounces. All of my road switchers and six axle units weigh in at about 18 ounces. I looked up on the NMRA website for locomotive weight standards, but they have none. Seems to me that a switcher such as the one I have should weigh at least 8 ounces.
Anyone have any experience with this?
Tom,I'm yet to find a need to push down on a BB SW7 get to move.
Sounds more like a pickup problem or she needs a good cleaning.
If you haven't already done so replace the metal pickup strip with wire.
Larry
Conductor.
Summerset Ry.
"Stay Alert, Don't get hurt Safety First!"
BRAKIE Tom,I'm yet to find a need to push down on a BB SW7 get to move. Sounds more like a pickup problem or she needs a good cleaning. If you haven't already done so replace the metal pickup strip with wire.
I haven't given it a comprehensive, good cleaning (yet), but I did replace the metal connector clip with a wire. I was thinking that the removal of that clip was enough to make it too light for consistent contact. I'll try cleaning it up good, see how it performs after that.
How old is the SW7? Does it have metal or plastic sideframes on the trucks?
I ask as I used one of the early ones (with metal sideframes) as the basis for one of my On30 loco conversions. Recently, I ironed out some bugs in the power pickup system which have symptoms similar to what you've described. If it is one of the early ones, I can walk you through what I did.
The Location: Forests of the Pacific Northwest, OregonThe Year: 1948The Scale: On30The Blog: http://bvlcorr.tumblr.com
You might also consider replacing the wheels with a polished wheel set from NWSL. I added weight to mine to improve its performance...
Simon
Listen to Simon! Simon Says..........replace the wheelsets with NWSL items. Inexpensive and a huge improvement in traction and electrical contact. It also wouldn't hurt to add weight to the engine as they are particularly light engines. Possibly a good cleaning of everything mechanical might help...........couldn't hurt!
oldline1
Regardless of what other fixes you do, if there's room I'd still add a few ounces of weight.
I have the right to remain silent. By posting here I have given up that right and accept that anything I say can and will be used as evidence to critique me.
Sounds like a pick-up problem to me, too...most likely the one that passes from the centre of the truck through the bolster on the loco's frame.I hardwired all of mine through all four contact points, and never had a problem with them stalling anywhere...
My locomotives were originally equipped with the cast metal AAR sideframes with outside bearings, but I replaced those with cast metal Flexicoil sideframes from Juneco. Those, in conjunction with interior weights, gave an over-all weight of 11.5oz. All four had the original motors and flywheels replaced with Mashima can motors, with no flywheels.When Athearn released the much better-detailed plastic Flexicoil sideframes on their inside bearing trucks, I re-equipped all four locos, and the weight dropped to 10.2oz.
Since my layout is mostly curves and heavy grades, I added additional interior weight, bringing each unit up to 12.5oz. These locomotives, still equipped with their original wheels, then became great pullers and very reliable electrically, with never a need to clean the wheels.
In general, the more weight you can fit into a diesel, the better it will pull. It's more or less the same for steam locomotives, with the added qualifier that the total weight of the locomotive-only should be balanced at the mid-point of the driver wheelbase.
Wayne
tbdanny How old is the SW7? Does it have metal or plastic sideframes on the trucks? I ask as I used one of the early ones (with metal sideframes) as the basis for one of my On30 loco conversions. Recently, I ironed out some bugs in the power pickup system which have symptoms similar to what you've described. If it is one of the early ones, I can walk you through what I did.
No, mine is a newer release, with the plastic sideframes. I haven't been "under the hood" on this locomotive in a long time, so it may be mucked up wi all kinds of crud, so I'll see if that works. I cleaned the wheels on it last fall (it hasn't been run much since then, as I moved and had nothing to run it on up til now). But, I don't think my wheel cleaning job was a very good one, so that needs to be addressed too.
Points all well taken Wayne. Although the motor in this loco runs fine, I have, at times, considered remotoring it. I don't think the motor is the root cause here, however. Having said that, like you, I do think there is a contact problem and the improvement of the contacts from the trucks through the bolsters is a very good suggestion. Also, in light of what you said about weight, I will, for sure, add about 4 ounces to the frame.
Maybe I missed it, but you didn't say where it was stalling. Is it on a turnout? Have you tried cleaning the track? Does it only stall in one place?
Marlon
See pictures of the Clinton-Golden Valley RR
E-L man tom Having said that, like you, I do think there is a contact problem and the improvement of the contacts from the trucks through the bolsters is a very good suggestion.
Tom,IMHO that would be a good place to start..One of my GP38-2s was acting a fool and upon checking I found the truck contacts was dirty.
Medina1128 Maybe I missed it, but you didn't say where it was stalling. Is it on a turnout? Have you tried cleaning the track? Does it only stall in one place?
Marlon, it is stalling in multiple places, including on turnouts, but not all turnouts, and, yes, I also need to clean the track, although all of the other locomotives that I have tested (and I have tested all but a few of the some 35 locos that I own), do not stall anywhere. I believe this is a problem unique to this locomotive.
BTW, I also have a LL P2K SW9, which weighs in at about 8.5 ounces compared to the 7 ounces that my BB SW7 weighs in at. That loco has no stalling problems.
More is better in the locomotive weight department. HO model locomotives have enough motor power to spin the drivers, and so tractive effort is coefficient of friction time weight on drivers. Coefficient of friction for metal on metal is about 0.20. Rubber traction tires raise the coefficent of friction to 0.75 or so. More weight on drivers, more tractive effort. Diesels with all wheels powered make weight on drivers the same as total locomotive weight. Steamers with pilot and trailing wheels and locomotives with only one truck powered have less than full locomotive weight on drivers.
At any rate, more weight gives more tractive effort. Pack in all the lead that will fit.
David Starr www.newsnorthwoods.blogspot.com
Where does one pack in the lead on a switcher such as the SW1200?
Bear "It's all about having fun."
That can be a problem. For the SW1200, perhaps some sheet lead fit into the top of the engine hood. Might work if you don't have a DCC receiver stuck up there. Or to the sides of the engine hood. Perhaps a sheet or two bonded to the cab roof with silicone bathtub caulk. Underneath the front and rear platforms. Underneath the walkways? Underneath the drive shafts under the engine hood?
Here's a look inside one of the SW1200RS locomotives shown earlier...
That's two blocks of lead at the front of the hood, then some sheet lead over the area of the motor, another custom-cast block of lead where the hood tapers, and another block affixed to the inside of the cab roof.
This view inside the cab shows one of the two blocks of lead which fill the areas inside the cab below window level...
This view of the body shell alongside of the frame shows that there's room for more weight between the two blocks at the front of the hood and the sheet lead over the motor.
I had omitted it because I didn't want to have to slice off those nubs poking through the top of the hood (mounting pegs for the number boards and bell). If I still had the other three units that go with this one, I would definitely add more weight there.I'd also cast weights to fit into the areas beneath the walkway steps - those alone would probably add another 3 or four ounces, plus perhaps 2 ounces for the missing one within the hood.
I'm just curious Wayne, How much does that locomotive weigh after adding all that lead?
As I mentioned in my earlier post, the final versions of those four locomotives each weighed 12.5oz.Here's all four of them on the Maitland River Bridge...
That flatcar trailing is followed by another 70 cars, and while the train is on a slight downgrade here, the same train made it up a 45' long 3.5% grade, which featured two horseshoe-type curves (in opposite directions) separated by 7' of the only straight track on that grade. The top of the grade is a series of S-bends.I'm pretty sure that those four locos could have handled even more cars, as I was able to run the same train on the same grade using four Bachmann Consolidations and again using four Athearn Mikados, neither of which singly were the equal of one of the switchers.I also ran the same train using four of the three loco types mentioned in various combinations, and placed in various locations within the train - head-end, pushers, and mid-train helpers.
Of the locomotives which I tested, these were probably the strongest...
...although the test was somewhat different and the results not conclusive because I ran out of cars for the test.I used a different section of track, also on a 3.5% grade, but the grade was only 16.5' long. Most of it was an S-bend. One loco could pull most of the 45 car train, which was just over 18' long, but couldn't quite make it to the top of the grade. When a second, similar locomotive was added, the train moved easily up the entire grade. Unfortunately, I had no more test cars (mostly two-bay hoppers with live loads, although there were several larger hoppers included. Total trailing weight was a little over 22lbs.
Here's the power...
...and here's what gave it the added oomph...
Each of the three locomotives weighed 33oz., and had a drawbar pull of approximately 8.3oz.
I've added weight to all of my locomotives, and with most of the layout's track on grades and curves, it was well worth the effort.
Whatever your contact problem is, it's not weight. I have an Overland NW5 that barely weighs eight ounces and it runs beautifully.Also, I must confess I am not a member of the "more weight is better" club. I have more locomotives than I can use already; I'd rather add an engine as needed.
Disclaimer: This post may contain humor, sarcasm, and/or flatulence.
Michael Mornard
Bringing the North Woods to South Dakota!
To your point Michael, I don't think that weight is the entire problem. I think that dirty track and dirty (sintered) wheels are a big part of it. And, as Wayne said, the improvement/cleaning of the contact from the trucks to the motor are a probable factor as well. I also think that a little extra weight can't hurt.
I have a small, 20' around the walls, industrial switching layout, so long trains are not happening here. The longest consist may be at most 10 cars. I also have more locomotives than I probably will ever use on this railroad (and cars too), so that too is not an issue. I do like the idea of trading out different locomotives and different cars though; just adds more variety and fun to it all.
Most locomotives usually have enough weight to maintain electrical contact with the track, although I often find that the tenders behind steam locomotives are a bit on the light side. If there are wires running between the loco and tender, extra weight in the tender can help prevent the wires from causing derailments - this was an issue with some early Bachmann DCC-ready locos. I run DC, so my locos are less fussy electrically, but I've added all-wheel pick-up to many of my steamers and the extra weight certainly doesn't hurt tracking qualities.Because much of my layout's track is on curves and grades, most trains run doubleheaded (and with pushers when necesary). This is necessary even with weight added to the locomotives, as there's limited room for it in most steamers.
I recently acquired another Bachmann Consolidation, and in the process of modifying it to match my existing ones...
...I discovered that I had never replaced the plastic air reservoirs on any of them!
All of the five locos went into the shop for modifications, which included new lead-filled air tanks made from brass tubing...
...and lead filings to fill the steam domes and sand boxes, along with another disc of sheet lead in the smokeboxes...
The four original locos are now back in service, while the newcomer is still in the shop getting its tender shortened and new paint and lettering for both cab and tender...
doctorwayne...how thick are those lead blocks that you have installed on those SWs.
bearman doctorwayne...how thick are those lead blocks that you have installed on those SWs.
I had a BB S12 which I improved by filling the inside of the hood with thing sheet lead. Could have put a reactor in place of the motor, since basically the whole thing was now lead-lined.
Once on the old club layout I decided to see just how far I could take this thing - so I stacked as much weight on the outside (on the walkway with the handrails holding it, on the roof, etc) and then tried to see how many cars I could start on the steepest grade ont he layout. Starting carefully kept the weight piled on top from falling off. Oh - this loco also had Ernst slow speed gears in it which magnified torque at the wheels. The more weight I stacked on top, the more cars it would pull - of course. ANd then eventually slip (I had NWSL wheels on it). Continued until I could stack no more weight without it falling off but even then it would end by slipping, not stalling. It was quite a large number of cars, around a curve as well. I don't remember the grade or just how many cars it was though. This was over 20 years ago. Far more cars than a small switcher should be pulling by itself, that's for sure.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Randy, it's surprising how much weight some locomotives can handle, if only there were room for it inside the body.I remember my disappointment in the pulling capabilities of the Athearn Mikados, and before I committed to the major job of increasing and balancing their weights, I did a test of one by draping a saddle of sheet lead, several pounds worth, over the boiler. Then, while holding the tender, I applied power and was surprised to see that it could still slip its drivers.This is an important consideration for anyone adding weight to any loco - if, when it's unable to move the trailing tonnage, the wheels don't slip, serious damage can be done to the motor, as it will continue to attempt to turn. The rapid build-up of heat can bake the insulation off the motor windings, rendering it useless.