Model Train Forum banner

1 - 16 of 16 Posts

·
Registered
Joined
·
302 Posts
Discussion Starter #1
All my engines are purchased second-hand, most from the 70's or older. Even my best engine (AHM GP18 from Yugoslavia) can only pull about 15 cars. My brother visited with a proto 2000 EMD E8 and it easily pulled a 35 car train. Are modern engines that much better than older ones? Or are six axle diesels that much better than four?
 

·
Registered
Joined
·
8,363 Posts
I don't really believe that the older locos were that
less capable of pulling as compared to today's locos.
Perhaps those with rubber band belt systems
might be weaklings but those with good gear trains
should do well but with a caveat: Weight.

Weight of the loco has much to do with it's
pulling power. It is very unusual for a loco
to stall, it normally slips wheels when trying to pull
a long train. More weight in the loco
adds to the wheel grip on the rails. In addition, the E8
mentioned has 6 wheel trucks...those extra
4 wheels plus the proper weight enabled the
extra pulling power that you saw.

Add some weight to your locos and watch their
pulling power increase.

Don
 

·
Registered
Joined
·
266 Posts
I have a couple old engines ive used bullfrog snot on and its almost miraculous the added pulling power that stuff gives. my tenshodo blue goose would barely drag a 6 car train when I got it now it will easily pull my 12 car rendition of the santa fe scout. I also used it on my nickel plate products brass pioneer zephyr and it was a night and day difference in that too
 

·
Registered
Joined
·
266 Posts
how does dcc or dc effect the tractive effort of a locomotive? I can understand that you can ramp up the power to the engine a little more controlled but that doesn't effect the true tractive effort of an engine?
 

·
Registered
Joined
·
302 Posts
Discussion Starter #7
I stacked 2 1/2 ounces of lead on top the engine and it pulled the 15 car train no problem. I got some Bullfrog Snot for Christmas but haven't had a chance to play with it yet (Must buy a transformer for the worktable...). Thanks to all for the help!
 

·
Registered
Joined
·
644 Posts
All my engines are purchased second-hand, most from the 70's or older. Even my best engine (AHM GP18 from Yugoslavia) can only pull about 15 cars. My brother visited with a proto 2000 EMD E8 and it easily pulled a 35 car train. Are modern engines that much better than older ones? Or are six axle diesels that much better than four?
If you like old 70s diesel models get yourself some Roco E7s. I have a few of them and they will pull more cars than I ever had room for on a layout.
They are as heavy as a brick and have huge motors that take up the width of the shell. (I read someplace that the motors are O scale but I’m not sure that’s actually true.)
The painting and details are horrible but you can usually find them custom painted/detailed on eBay.
I have a couple of the AHM GP18’s. They are very light. As was mentioned, you definitely should add weight but even then, a Roco would probably out pull them 10-1.
 

·
Registered
Joined
·
1,645 Posts
HONESTLY ITS MORE ABOUT CONTROLLING SYSTEMS LIKE DCC VS DC
An engine that spins its drivers at 4 oz of resistance will do so regardless of whether it gets DC voltage or DCC voltage. IOW, the type of controlling voltage is completely irrelevant. The reason: can motors are DC only, and that's what they get from decoders: rectified AC square wave.

What limits the tractive capacity of any one locomotive is its ability to apply power to the limit of friction between the driver's tire surfaces and the rail bearing surface. When the drivers begin to spin, that's when more weight helps. If you keep adding weight, you will eventually cause a stall.
 

·
Registered
Joined
·
604 Posts
Many of those old AHM locos are good candidates for a repower. Especially the ones with 8wd. You might never get to 35 cars but a new motor and more weight can greatly increase the number of cars they pull.

Also Athearn from the same era will likely pull better even before a motor swap.
 

·
Registered
Joined
·
3,341 Posts
Even my best engine (AHM GP18 from Yugoslavia) can only pull about 15 cars. My brother visited with a proto 2000 EMD E8 and it easily pulled a 35 car train.
Not surprising...
FWIW, these comparisons are probably typical.
Four-axle Geeps are (quite naturally) far inferior pullers than a typical (much heavier) 6-axle E unit.
It's not surprising that an E8 model would pull at least twice as many cars as a Geep.
 

·
Registered
Joined
·
626 Posts
I'd suggest older Proto2000 SD7s/SD9s, and GP7s/GP9s. Many "new-old stock" items available for good prices, lots of road names.

Generally very smooth runners, good pullers, most are easily converted to dcc.

The GP's will probably need the wheels/axle gears replaced, as they have a history of cracking (but it's a cheap fix, Athearn wheelsets can be substituted).

The gearboxes often need to be "cleaned out" of the old grease, which hardens to a peanut-butter-like goo.
 

·
Registered
Joined
·
3,645 Posts
Four wheel drive vs. 12 wheel drive?

All my engines are purchased second-hand, most from the 70's or older. Even my best engine (AHM GP18 from Yugoslavia) can only pull about 15 cars. My brother visited with a proto 2000 EMD E8 and it easily pulled a 35 car train. Are modern engines that much better than older ones? Or are six axle diesels that much better than four?
Murv2;

How many of the four axles on your old locomotives are powered? That is, actually gear-driven, not just wired to pick up electrical power. Many older, cheap locomotives, including some from Yugoslavia, had only two axles, both mounted in the same "power truck" assembly driven by gears and a motor. The other truck also had two axles in it, but those axles were free-rolling, and did nothing to drive the loco along the track, or pull any cars. If you scroll down a few threads in this HO forum you will come to a thread called "Power truck disassembly" posted by "HOFAN." It has a photo of this type of locomotive with only one truck that is powered.
If any of your old locomotives are built this way, then it's small wonder that they can't pull as well as your brother's E8, which probably has all six of it's axles powered. Even if your old locos have four axles driven, that still isn't likely to pull as well as a loco with six axles driven.
You may have noticed that most of the real locomotives around these days have six axles, and yes, they are all powered. The reason for this is that trains keep getting longer, and heavier, and locomotives keep getting designed with more horsepower to pull those longer, heavier, trains.
That horsepower won't be much use without the traction it takes to get the train moving, and keep it moving. That's where the twelve wheel drive and the increased weight of the bigger locomotives, comes into play. Generally speaking, the more weight that can be put over more driving wheels driven by more horsepower, the better a locomotive will pull.

Traction Fan :smilie_daumenpos:
 

·
Registered
Joined
·
604 Posts
Murv2;

How many of the four axles on your old locomotives are powered? That is, actually gear-driven, not just wired to pick up electrical power. Many older, cheap locomotives, including some from Yugoslavia, had only two axles, both mounted in the same "power truck" assembly driven by gears and a motor. The other truck also had two axles in it, but those axles were free-rolling, and did nothing to drive the loco along the track, or pull any cars. If you scroll down a few threads in this HO forum you will come to a thread called "Power truck disassembly" posted by "HOFAN." It has a photo of this type of locomotive with only one truck that is powered.
If any of your old locomotives are built this way, then it's small wonder that they can't pull as well as your brother's E8, which probably has all six of it's axles powered. Even if your old locos have four axles driven, that still isn't likely to pull as well as a loco with six axles driven.
You may have noticed that most of the real locomotives around these days have six axles, and yes, they are all powered. The reason for this is that trains keep getting longer, and heavier, and locomotives keep getting designed with more horsepower to pull those longer, heavier, trains.
That horsepower won't be much use without the traction it takes to get the train moving, and keep it moving. That's where the twelve wheel drive and the increased weight of the bigger locomotives, comes into play. Generally speaking, the more weight that can be put over more driving wheels driven by more horsepower, the better a locomotive will pull.

Traction Fan :smilie_daumenpos:
This is key. I'm fairly sure that the AHM GP18 came in both 4wd and 8wd versions. I have a SOO and two different NW versions, but I don't recall which versions they are. I'm told they're actually pretty easy to upgrade with one of the $3 Ebay Mitsumi motors. Haven't done it yet but I've got the motors and the locos, so it's just a matter of time.
 

·
Registered
Joined
·
302 Posts
Discussion Starter #15
Murv2;

How many of the four axles on your old locomotives are powered? That is, actually gear-driven, not just wired to pick up electrical power. Many older, cheap locomotives, including some from Yugoslavia, had only two axles, both mounted in the same "power truck" assembly driven by gears and a motor. The other truck also had two axles in it, but those axles were free-rolling, and did nothing to drive the loco along the track, or pull any cars. If you scroll down a few threads in this HO forum you will come to a thread called "Power truck disassembly" posted by "HOFAN." It has a photo of this type of locomotive with only one truck that is powered.
If any of your old locomotives are built this way, then it's small wonder that they can't pull as well as your brother's E8, which probably has all six of it's axles powered. Even if your old locos have four axles driven, that still isn't likely to pull as well as a loco with six axles driven.
You may have noticed that most of the real locomotives around these days have six axles, and yes, they are all powered. The reason for this is that trains keep getting longer, and heavier, and locomotives keep getting designed with more horsepower to pull those longer, heavier, trains.
That horsepower won't be much use without the traction it takes to get the train moving, and keep it moving. That's where the twelve wheel drive and the increased weight of the bigger locomotives, comes into play. Generally speaking, the more weight that can be put over more driving wheels driven by more horsepower, the better a locomotive will pull.

Traction Fan :smilie_daumenpos:
The GP18 has all wheels driven. I have a couple other AHM that only have two axles driven and I don't expect much out of them. I've glued the weights under the hood of the GP18 and it pulls much better now. Bullfrog snot is the next thing, for an old Aristocraft ten-wheeler with giant drivers and no traction.
 
1 - 16 of 16 Posts
Top