Tender Drives

[superturbine]

I think we are missing out on a variety of steam engines by insisting that we have locomotive powered steam engines.


Here is my argument for tender power-  What say YOU?
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Don't worry the engine will not be painted Grey Hound!  Brunswick green after Milwaukee Paint.

[chicken45]

1. Can I send you a Broadway Limited set in lieu of payment for more shells?
2. Do you have close up pics of the tender? I'd love to see how the truck side plates you cast fit in there.

[superturbine]

1-Ha! It is a crime the T1 pulling all of those Armor Yellow cars!  Sure, the T1 would look better.  Let me know if you need any replacement parts.... (currently).  The S1 should be Cast soon, just trying to catch up on other casting projects not revealed.

2- I have considered my T1 tender as a test-bed, the trucks have been moved several times, so they don't look so hot.  I need to install another set.  Although painted no one will ever know.  My plan is still to use the NStars Tender drive, I believe its still on time for the Milwaukee N scale convention (no pressure guys).

[Lemosteam]

Jason that is impressive pulling power and I am no stranger to what NStars have done with tender drives.  I would however like to know what YOU started with and how you fitted that into the tender. 

I have no issues with tender drives per-se but I do think it is more romantic when one can achieve similar pulling power under the boiler.  To me it is less of a mechanical challenge to plunk a large, weighted mass over a drive mech into the tender and allow the lcomotive to freewheel.

When I see Max's work, I am always astounded at how well his locomotives run after all of his cutting and fitting, unlike mine that to be quite honest, don't always run so hot after I tinker.  I would cite eric220's (Magliaro'd) K4 video pulling 25+ cars on the level, or my K4 pulling 15 cars up a 3%+ grade.  I think the challenge of getting a locomotive to be the powered mechanism makes the kitbash worth all of the work.  As you know I'm unconventionally hoping to have both the tender and the locomotive powered in my T1, as an experiment.

Yeah, you need a BL behind that T1, and we might permit one UP sleeper in there...   

[keeper]

There is nothing wrong with tender drives. I have some Fleischmann steamers and I think one Minitrix steamer with tender drives. All run perfect.

Thomas

[rogergperkins]

The whole idea of placing the drive in the tender or alternate car is in line with my question about a DCC sound unit in an alternate car which could run with
various locomotives.

[jdcolombo]

I'd do tender drives in a heartbeat if there were some sort of standardized mechanism or even a "tinkertoy" parts system that you could assemble with relative ease.   The LifeLike Berkshire, which is the mainstay power on my 1957-era NKP layout, is a very-highly-detailed, wonderfully-smooth loco that won't pull anything out of the box.  I've modified mine with "poor man's traction tires" (a strip of thin Scotch double-sided tape on the #4 drivers) to overcome that, but I'm still limited to about 30 NMRA-weighted freight cars on level track.   I'd love to have a tender-drive unit that could make these things pull more like 50 cars on level track and 30 up a 1.5% grade.

I wouldn't miss the "romance" of a boiler drive at all.  However, I do note that Kato has achieved superb pulling power with teh GS-4 using a sprung driver mechanism with traction tires, so maybe in bigger steam, tender drive wouldn't be necessary to pull prototype-looking consists. 

John C.

[sizemore]

I'd do tender drives in a heartbeat if there were some sort of standardized mechanism or even a "tinkertoy" parts system that you could assemble with relative ease.   The LifeLike Berkshire, which is the mainstay power on my 1957-era NKP layout, is a very-highly-detailed, wonderfully-smooth loco that won't pull anything out of the box.  I've modified mine with "poor man's traction tires" (a strip of thin Scotch double-sided tape on the #4 drivers) to overcome that, but I'm still limited to about 30 NMRA-weighted freight cars on level track.   I'd love to have a tender-drive unit that could make these things pull more like 50 cars on level track and 30 up a 1.5% grade.

I wouldn't miss the "romance" of a boiler drive at all.  However, I do note that Kato has achieved superb pulling power with teh GS-4 using a sprung driver mechanism with traction tires, so maybe in bigger steam, tender drive wouldn't be necessary to pull prototype-looking consists. 

John C.

You can get 50 cars out of your berk...you only need to cut a groove for the TT.

These are OOTB cars on a HCD plain oval. When I went to a friends layout for shakedown tests, it would only pull about 23 cars but there were a lot of factors at play between the cars, track and layout. The ACME Lab is already working on a second version improving on the short-comings between the dual decoder setup (FL4 for lights and Tsunami for motor/sound), and increasing the weight on the drivers.

The S.

[mmagliaro]

I have never owned a tender drive, but I see a lot of promise in them. 

Pros:
1.   Assuming you power both trucks, you have two very free-floating and pivoting trucks,
so it's easy to keep all 8 wheels planted on the rails. and just like a diesel,
you can get much better pulling power out of something like that.

2. The wheel diameter is only 36", not 50, 68, or 80, so you automatically get a splendid speed reduction
and a lot more torque.  This is key to making an engine that powers through curves and up hills with dead-steady
performance.    I'm doing it with gearheads and other types of gear reduction, but doing it on the tender wheels
is equivalent and less expensive.  You would put a conventional motor with big flywheels in a tender
for $30-$40 and get the same performance I am getting out of a high-end gearmotor that costs
more like $100.  In fact, a revved up motor with flywheels should run even better.  The devil is in the details, of course.
You have to make the gearing and universal joints to the trucks work really smoothly.  But heck, Kato and others
have been doing that in diesels for years.

3. Powered drivers on a steam loco will always tend to "fight" their way through curves somewhat.  You
are taking something that is long, rigid, and that wants to move in a straight line, and you are ramming it through a curve.  This is
not much different than how a real steam loco pushes through a curve.   Good bearings and smooth lateral
play in the mechanism helps somewhat, but will never be as good as a short, pivoting, powered diesel-style truck.

4. On all but very small tenders, you can get a bigger motor in a tender than you can in the loco itself.

Cons:
You don't have the true prototypical accuracy or "romance" of an engine-powered steam drive.

All of this makes it sound like I "oppose" conventional steam drives.  I certainly do not (heck, that's all I've ever built).
I'm just pointing out that from a purely mechanical point of view, a tender drive has a lot of things going for it.

A "breadboard" tender drive frame would be a great product.   Create 2 or 3 standard power trucks (some 2 axle
and some 3 axle) with gears and a U-joint connection on them.  Now you plunk them into any floor you build,
mount the motor in the middle and connect the U-Joints, and you're set.   You could have a tender of any length
you want, and still use the same basic mechanism with different length U-Joint connections.

--------------------------------------
The T1 is a rare bird.  It has the duplex drive behavior and if you really want to mimic that, yes, you'd have to put
motors in the engine.  But that strikes me a very small point.

[superturbine]

Good analysis Max,

Another consideration for a tender drive is- build time.  In its current form my tender drive took approx 3 hours.  Cost -$40.00, replacement parts if needed- readily available. 

John-
The Big question..... what is it?  No romance here!  Kato RDC. Current weight over 4 ounces with more to be added.

2 powered trucks, but of course only 4 powered axels.

Surprisingly there was very little height clearance over the rear truck.  This eliminated the use of numerious other kato mechs. 

Of course it runs extreamly smooth and quite and I am happy to scrap an RDC to build a T1.  Well, I am happy to scrap an RDC for any steam engine!

Of course I admit, there are a host of issues, undersize tender wheel.... but you cant see them.
Difficulty in added the 2 extra wheels to the trucks.
The motor is very low and partially visible at the bottom of the tender.

Perhaps there was a better solution.... but the RDC has functioned well up to this point.  Its only a temporary drive solution, but some of would be very happy with it.

[peteski]

Ah, the pros and cons of tender drive again.  Didn't we just recently have this discussion on another thread?    Just as I stated there, I see nothing wrong with the tender drive concept (except that it leaves much less room for a potential sealed speaker enclosure).

Max, Re pivoting trucks:  My tender drive experience is with European locomotive models and most all have rigid wheelbase with some sideways axle play.  Many smaller US tenders (with pivoting trucks) will work perfectly well if the trucks were to be made rigid (non-pivoting).  But that wouldn't be optimal for the larger/longer tenders.  However, larger thenders usually have sideframe details which pretty much cover the wheels which will nicely hide the mechanism.

[peteski]

Jason, how about using Kato S2 NW2 trucks. Very similar to the RDC, but with bigger wheels.  Why did you have to mount the motor so low?  The drive shafts have universal couplings and that should allow them to angle up to a higher mounted motor.

[superturbine]

Well, I was ok using the truck because the tender sits so low you cant see much anyways, but its a good idea.  As for motor height, the space between the motor and the 2 trucks is very tight, the universal could not be mounted at much more of an angle.  Infact, my trucks are spaced a little too far apart as compared to the proto.  I suppose this was one of those " I will give it a shot" deal.  I dont want to spend any money, I hate RDC's and I will be replacing it with a Nstars tender.  But the tender turned out a little better than I thought it would.

[Lemosteam]

Ah, the pros and cons of tender drive again.  Didn't we just recently have this discussion on another thread?    Just as I stated there, I see nothing wrong with the tender drive concept (except that it leaves much less room for a potential sealed speaker enclosure).

Max, Re pivoting trucks:  My tender drive experience is with European locomotive models and most all have rigid wheelbase with some sideways axle play.  Many smaller US tenders (with pivoting trucks) will work perfectly well if the trucks were to be made rigid (non-pivoting).  But that wouldn't be optimal for the larger/longer tenders.  However, larger thenders usually have sideframe details which pretty much cover the wheels which will nicely hide the mechanism.

peteski,

I'm glad a separate thread was started because it was overtaking Jason's T1 thread progress.  At least we can keep the discussion here.

Yeah, but NOW the speaker can be put up front where ther sounds come from anyway!

[peteski]

Well, I was ok using the truck because the tender sits so low you cant see much anyways, but its a good idea.  As for motor height, the space between the motor and the 2 trucks is very tight, the universal could not be mounted at much more of an angle.  Infact, my trucks are spaced a little too far apart as compared to the proto.  I suppose this was one of those " I will give it a shot" deal.  I dont want to spend any money, I hate RDC's and I will be replacing it with a Nstars tender.  But the tender turned out a little better than I thought it would.

Again, S2 NW2 has a "transfer case" gearbox which allows its trucks to sit close together while the motor is mounted much higher. It is actually pretty ingenious!  But if you are going with another option then you're all set.

Don't hate RDCs!  Boston & Maine (which I model) had lots of them on their roster, and Kato's model is very good.