USAT SD40-2

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Overview:

A nice loco, using the standard 3 axle USAT motor block.

Wiring for DCC:

USAT locos are "fun" because of all the different voltages and types of lights and weird commons, etc. R.J. DeBerg and I did this conversion by long distance, me with pictures and manuals, and him with the loco, from San Diego to Cumming, Georgia!

The picture below shows what you will find inside, the main board on the left (that has the switches on it) and the smoke regulator/control board on the right.

The picture below gives a closer look. I believe the three terminal regulator on the left is for the smoke power.

The picture below has an even closer view, and these two pictures will help locate the wires and connectors described next:

There are several connectors on the "upper" side of the board, will start at the upper left side, at #1, going to the right

Connector #1: upper left side (rear headlight and number boards)

3 pin connector with white, yellow, green wires, reading left to right

green - common - connect to decoder common (NCE D408 blue wire) (was positive in the USAT wiring)

yellow - number boards - two screw in incandescent bubs in parallel - connect to 133 ohm resistor then to ground (we used 2 diodes connected anode to anode, cathodes go to the rails, since NCE decoder does not have a ground. The makes the number boards always on

white - rear headlight- incandescent bulbs in parallel - connect to 200 ohm resistor then to decoder rear headlight (NCE D408 yellow wire)

note: voltage to these lights is between 3.5 and 4 volts

Connector #2: second from left (front headlight, number boards, strobe/beacon light on roof, cab light)

3 pin connector with white, red, black wires, reading from left to right

white - common - connect to decoder common (NCE D408 blue wire) (was positive in original USAT wiring)

black - front headlight - 5.5v- 70 ma - from 20v - connect to 200 ohm resistor, 1 watt then to decoder front headlight (NCE D408 white wire)

red - number boards, beacon, cab light - 6.2v - connect to 100 ohm resistor then to ground (we used 2 diodes connected anode to anode, cathodes go to the rails, since NCE decoder does not have a ground. The makes the number boards always on 

Connector #3: third from left - silkscreen on board says LED4 (rear classification lights)

2 pin connector with black and white wire

These go to red LEDs, 50 ma, running at track voltage,  There is a dropping resistor and a diode in the stock wiring, leave them

Connector #4: third from right side - silkscreen on board says LED (front classification lights)

2 pin connector going to the front class LEDs

"Connector" #5: second from right side

There is no connector here, the wires to power the smoke unit are soldered to the main board

Connector #6, at upper right of board has "S" silkscreen above it

This is power output to optional sound system, controlled by sound switch on main board.

There are small circuit boards that have the lights and the wires. The pictures below show the board in the back of the loco.

More shots:

The following two pictures help you see the wiring of the boards, and you can see the common that connects to the outer shell of the sockets and to the red wires of the headlight lamps.

The following picture shows the board that is in the front. I need R.J. to write up what he had to do to get to this board, it is "buried" in the cab.

And just for fun, here's a picture of the conversion in process, you can see the NCE D408 board near the rails, and a Phoenix sound board mounted in the end of the chassis by it's backup batteries. The amount of current drawn by the incandescent lamps calls for high wattage resistors!

More wiring notes:

Rear truck is motor2 and pick2

The way you can tell which connector from the truck is the pickups and which is the motor, is the track pickups have 4 wires going into the connector, and the motor has 2. (The pickups are 4 wires because one wire is the "skate" and the other wire is to the bearings in the sideframes that also pick up power from the axle tip, and thus the wheel.

Best thing to do is disconnect the existing JST's and wire up some new ones, or you can unsolder the wires from the board. Either way, make sure you leave the original wires and connectors on the trucks to remove easily for maintenance or disassembly.

DCC wiring:

The right hand rail pickups go to the decoder red wire.
The left hand rail pickups go to the decoder black wire.
The motor leads go to the orange and gray wires. (hook them up and reverse them if the loco runs backwards.)

There is a way to get the motor "right" the first time, put power to the motor from DC, when it runs forwards, the wire that has positive voltage from your supply is the "motor +" lead, connect to the orange wire. Most times it just as well to try it and see if you got it the first time.

Be sure to do this on rollers, in case you wire one truck backwards.

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SD70 MAC

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General:

The SD70 is a big and long locomotive. It uses the same 3 axle trucks as other USAT 3 axle truck diesels, with one axle pivoting. All axles are powered. Some earlier ones came with one axle per truck fitted with traction tires, newer releases have no traction tires.

Ted Doskaris weighed his at 10.56 pounds. Somewhat light for such a big locomotive.

Derailments caused by length and coupler swing.

The #1 complaint about this loco is it derailing the car behind it. USA Trains indicates it will traverse 8' diameter curves. In a twisted sense this is true, but usually the body length combined with the body mount coupler and the restricted swing of the coupler normally derails the car the loco is pulling. Here's some tips:

Modifying couplers for 8' diameter curves

Yes, it is possible! James Kuhns brought his by, and I've got some pictures here. More descriptive text will be added soon. Basically he modifies the coupler assembly and the pilot to allow greater swing, and removes the centering springs. You may have to use a car behind the loco with equally long coupler swing also. James has had success with the modern tank car, and an added benefit is it's weight due to the all metal construction.

The picture below shows the modification to the interior piece that also limits the coupler swing. The upper picture shows the modification needed.

The picture below shows the modifications to the pilot that allow the increased coupler swing:

The picture below shows the modification to the coupler. The centering springs must be removed, and the bosses to retain the spring must be removed.

Norm Baullinger found he still needed even more "swing" with shorter cars, so he modified the coupler to put a swivel joint near the knuckle:

A video showing an interesting result of limited coupler swing (courtesy of Nicolas Teeuwen)

What appeared to have happened:

1. coupler swing limit reached early in curve

2. this side pressure locks couplers together, not allowing couplers to slide up and down naturally

3. as the loco hits the top of the grade, the rear coupler lifts and also lifts the truck of the trailing car

4. as the swing limit is "relaxed" the couplers are no longer locked together, and the release of the lock allows the trailing car truck to drop back down, exceeding coupler overlap and uncoupling.

Nicolas solved this by opening up the slot, but not makeing the spring modification.

Disassembly:

There are 10 large screws that hold the body to the chassis, but there are also 2 very small screws that hold the cab on. They are located at the rear of the cab underneath, at the very outside edges of the frame.

Here are a few pictures of the main board in the loco, it's larger than most, maybe because of the ditch liights, or just because there is room:

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2-8-0 Consolidation

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Consolidation History

Aristo-Craft had announced / talked about a Consolidation style loco for several years, and it was delivered just before mid year 2011.

Here is a prototype picture, notice the blind driver, more later.

 '

The Prototype

Aristo has stated the prototype for their model is the B&O E27 class.

Here is B&O #2527 (from the North East Rails Steam Roster, http://www.northeast.railfan.net) that seems to be pretty darn close but the air pumps are in a different spot. This series was built by B&O themselves, I believe, in Richmond and Schenectady.   The one below has the air pumps in the right spots, but the sand dome in a different spot, ladders different:  

Even closer is #2846 below, but the air tank on different side: I'm still looking for the nearest Santa Fe prototype.

The "blind driver" story

Originally, the loco was going to be supplied with blind drivers only., (For many years Lewis told me how disappointed he was in the Mallet and Mikado sales, and that this was because of the larger radius track they needed). Thus the blind drivers. (Of course the reason for the poor sales of the Mikado was because of the many slipping drivers and destroyed side rod gear. The Mallet suffered the same problem)

Later, according to Lewis, the center 2 drivers will be blind, but (from Lewis)  "we will deliver extra flanged drivers at the time of delivery of the loco if anyone wants to change. They will not be free, but it will be an easy upgrade."

This actually changed to "the loco will be delivered with flanged drivers, but the blind drivers will be included"

Later this changed again, and "the loco will be delivered with flanged drivers, and you can get blind drivers if you want later"

The final incarnation in 2011 is that the official position is that it's too difficult for you to remove the drivers yourself, because of the new system to fix the wheels to the axles, so blind drivers will not be available at all".... hilarious story considering all the discussions over and over.

In the end the customers won, their first request was all flanged drivers. Good. (And a normal human can remove the drivers, more below)

Other changes expected: The Aristo socket will be in the tender, so no extra wire for the sound board from the loco to the tender. 

Mid 2011, it was announced that there would be a new method of fastening the drivers to the axles.

Delivery, mid year 2011

I received my Consolidation in July 2011.

In the top foam half, there's a number of things, clockwise from lower left:

• Lower left, two packages, one with an aristo knuckle with a short shank, another with an aristo knuckle with a longer shank, and a hook and loop coupler.
• Far left, a small packet with what appears to be 2 cab window shades and steam dynamo.
• Upper left, a hook and loop coupler with a 4mm screw.
• Upper right, a 5 ml syringe. 

WARNING! The syringe did NOT have a "SAFE" tip, it is a normal sharp hypodermic needle. I recommend you immediately take it out and grind the tip flat and blunt if your looks like this.   Update: In November 2011, Lewis Polk addressed this issue, and changed from a standard medical syringe to a plastic tipped one. I have not seen the new one, but thanks for correcting this Aristo-Craft.

Below is a picture of the cab window shades, and what I believe to be the steam driven generator or "dynamo"

Removing the top foam insert, you reveal the loco with a nice plastic sheet protecting the finish. There is a long block of foam under the motor block that supports it

The loco weighs 8 pounds 5 ounces. It looks great. There's a higher level of detail, for example, note that the handrail stanchions are much smaller, and the handrail is now metal, not plastic. All of it is more to scale and looks much better.  

The tender has a similar plastic sheet. It weighs 3 pounds, 5 ounces. This is significantly heavier than any other Aristo tender.  Good!

Wheels / gauge / flange measurements  

Right off, this is a huge disappointment with this loco, especially in light of the new "wheel attachment system". The wheels have improper gauge, and a terrible wheel contour. The nominal tread diameter is 1.91". I say nominal because measurement of the tread diameter near the flange is impossible, more later. The spacing between the drive axles is 2.19"

Previously, all the "prime mover" based locos always had a wheel back to back measurement that was too narrow. The wheel gauge was ok, but the flange was too thick.

So this means on straight or curved track the loco would run fine, but running through switches, the out of specification (both NMRA and G1MRA) back to back allowed trains to derail, hit the frog, etc. In addition, to accommodate this situation, the flangeway widths in switches had to be made wider, thus making even properly designed wheelsets have problems.

For steam locomotives, the reason the wheel gauge was right and the back to back was wrong is because the flanges on the wheels were way too thick. Since the wheel gauge is a result of the back to back spacing plus the thicknesses of the flanges, it's a physical certainty that overly thick flanges ensure you CANNOT have correct wheel gauge AND correct back to back measurements at the same time.

Well, the news is that these wheelsets are still out of specification, but in a different way and the wheel contour is worse. Now the back to back is correct, but that makes it a physical certainty that the gauge will be out of specification, and indeed on the 4 locos recently measured, ALL of them had a wheel gauge in excess of 45mm, i.e. the wheel gauge is WIDER than the track !!!

To contribute to the problem, the "fillet" between the wheel tread and the flange is a huge radius, so you "lose" about half of the tread width. The result is a "press fit" in between the rails. Seriously.

Here's the measurements on a new consolidation (as delivered ), and on some Aristo track: Here's the actual measurements from the review sample, provided to Garden Railroader from Aristo: (Keep in mind that the original review only measured the back to back, and the reviewer neglected to include the wheel gauge. The first numbers for wheel gauge were measuring INTO the fillet, not the extent of the thread. After some more work, the reviewer provided the information that he had measured to the center of the fillet, and this was about 0.024"... so you will see the measurements below taking the reviewer's first "gauge" measurements, and then adding in the correction for measuring too narrow because of the fillet (having to add 0.024" on each side, so a total correction of 0.048" (reference this thread in MyLargeScale.com) http://www.mylargescale.com/Community/Forums/tabid/56/aff/17/aft/123905/afv/topic/afpgj/4/Default.aspx

Axle 1 - 1.771" + 0.048 = 1.819" ( equals 46.2 mm, WIDER than the track gauge)
Axle 2 - 1.769" + 0.048 = 1.817" ( 46.15, wider again)
Axle 3 - 1.762" + 0.048 = 1.810" ( 45.974 mm)
Axle 4 - 1.758" + 0.048 = 1.806" ( 45.87 mm)

I need to clean the rest of the numbers up below, but this data above is again, from the reviewer and the loco in the GR review.  

Here's some numbers from a friend's loco  

rear driver 39.97 - 45.25
next forward 39.53 - 45.07
next forward 39.53 - 45.13
front driver 39.86 - 44.33

Here's some track gauge measurements from Aristo track:

new piece of track 45.23
used piece 45.09 - 44.85
used curve 8' diameter - 45.31 - 45.08    

Notice the wobble side to side on the following video. Watch at 2:30, watch besides the wobble from side to side, how the cowcatcher rides up and down. This is from the gauge problem, making the loco ride up on the flange effectively. Watch at 2:52, the wobble is extreme.  

(Video below courtesy of Chris Haon)

Here's worse, watch at 1:47..

(Video below courtesy of Charlie Zimmerman)

I'm interested in fixing this problem, so I decided to see the new "wheel attachment system" myself, although Aristo says you cannot take the wheel off yourself (and used this as a reason for not providing blind drivers).  

The way I removed the wheels was to use a Bernzomatic model ST250K micro torch and heated the axle screw.      

This torch has a pin point flame. I used the lowest gas setting, which gave me a flame about 1/2" long, and applied it to the screw head directly, about 30 seconds. I then waited about 30 seconds for the heat to distribute. I then heated it again for about 30 seconds and immediately removed the screw. Thanks to R.J. DeBerg for this technique.  

Be sure you find a perfectly fitting screwdriver, and have the loco in a cradle or supported so you can bear down on the screwdriver and apply force while unscrewing. Don't let it cool before trying.  

Below is the new bushing, it is steel and pressed into the driver. The knurling makes it so it does not slip in the wheel. Notice the red loctite slathered all over inside.    

Below is a better picture of the insert: (it sticks out about 1.43 mm)    

The bad news is that it appears that the bushing is tapered also! So the obvious question: "can you reposition the bushing to adjust gauge" is apparently no, it's not going to work.

Now I need to investigate further if it can be pressed in further without damaging the casting, or can I press it out, enlarge the hole in the driver and press it back in deeper.  

The picture below shows the front side. You can see the darker steel color in the casting. The lock washer bears on this steel bushing.       Well, even though I gave some thought to just press the bushing in further, I'm a little cautious. And good thing, I was wrong, the bushing is not tapered, there is a lip in the wheel that provides a positive stop for the bushing, look carefully inside:    

Here's the bushing. The end with the chamfer goes into the back side of the wheel first, and that is the end that has the smaller inside diameter.  

And here is an end view, the end that sticks out of the wheel, nearest the gearbox. You can see the taper inside:  

So, my next thought is to possibly reduce the size of the lip, or drill it out altogether, and then press the bushing in to meet NMRA and G1MRA specifications, after I have machined the back side of the wheel to thin the flange to NMRA / G1MRA specs (about 1.5mm is my target).  

An interesting post, showing you how Aristo still cannot admit the truth of the wheel gauge being incorrect: http://groups.yahoo.com/group/gscalerailroading/message/89   Just friggin' unbelievable, here are the numbers, corroborated by many, yet Aristo seems to believe that it's someone's track.    

 First run OK, so RJ tells me I'm not being fair in being upset about the gauge measurements, and I need to try running it before I take it apart.   Take it to the back yard. I think the manual is backwards, remove the coal load by pushing on the rear of the load and lift up. Looks like it might come out the other way, but harder to do.   So I am not surprised at what I see, because I saw the prototypes. There is a big board very near the top of the tender, about 1/4" clear of the speaker. The QSI board barely fits. The Aristo circuit board is placed way too far back in the tender. I guess it was easier to make the standoffs start after the tender weight.  

Suggestions to Aristo:

(These were written while Aristo was still in business, in the hopes they would correct the issues)

SUGGESTION TO ARISTO-CRAFT: MODIFY THE MOUNTING OF THE BOARD TO CENTER IT IN THE TENDER OPENING, ENSURE THAT ALL CONNECTORS ARE ACCESSIBLE WITHOUT REMOVING THE TENDER SHELL (all this would take is to make mounting posts for the board that come up through the weights, simple, also this might allow a larger speaker).   Well, that makes it very hard to use the socket, as the back of the socket is about even with the rear of the opening. Poor design. I plug in my QSI board, after being VERY careful to get the pins aligned, since you really cannot see them. Oh, guess what? You cannot put the coal load back on because the 2 clips hit the QSI board. I'll bet they hit the Revo board too. Why the heck the 2 clips are in the center of the coal load, instead on the sides where they would clear everything?   Check the battery/track switch, turn on the lights switch... and there's another on/off switch with no visible label... why? (look at the top right switch) Turn that one on too. The smoke switch has a label on it to warn you about using fluid.  

SUGGESTION TO ARISTO-CRAFT: LABEL THE UNLABELLED SWITCH   Now to run the loco on the new decoder: Press 'select'  - '3'  - 'enter' and run the loco (eat your heart out Revolution users) and the loco moves.... BACKWARDS.... yep, they wired the DCC socket backwards from specifications.  

SUGGESTION TO ARISTO-CRAFT: WIRE THE MOTOR LEADS CORRECTLY TO THE SOCKET SO THAT USERS DO NOT HAVE TO USE REVERSE TO GO FORWARDS, I.E. MEET THE NMRA STANDARD   Set the direction to reverse and off it goes, nice and smooth and quiet.... yeah quiet? Oh, forgot to hook up the cable to the speaker.   ( I later rewired the loco to correct polarity, swap the wires 5 and 6 where the wires come from the plug. In the photo above, you can see the 8 wires just to the left of the socket, and wire 8 is labelled on the board.   Before trying to bring up the sound, I check how the loco sits on the track. BAD. The front and rear drivers are TIGHT in the rails. Aristo 10' diameter SS track. TIGHT, they are wedged into the track, no side play at all.   Try sliding the center drivers, they move.... Weird, because the gauge measured the same, how can they have play? Uh oh, another problem? Yep, the center drivers seem to have some side to side play because they are NOT in line with the end drivers, they are slightly off the rail, so they can twist a bit side to side. The motor block casting must be warped or something else. So only 2 of the 4 drivers are touching the rail heads. This might also be because the outer drivers are wedged in the rails, and riding on the fillet, thus raising them up off the rail head. I am not pleased.  

SUGGESTION TO ARISTO-CRAFT: YOU MUST HAVE A PROPER THICKNESS OF THE FLANGE TO BE ABLE TO HAVE BOTH WHEEL GAUGE AND BACK TO BACK AT THE SAME TIME. YOUR CURRENT WHEEL CONTOUR MAKES THIS IMPOSSIBLE.   Electrical: Before going further, I notice that the cab light, marker lights, number boards are all wired to the headlight... so go in reverse all these lights go dim, instead of just the headlight (default QSI is dim in reverse not completely out). Dumb, but a "cheat" to use fewer wired from the tender to the loco I would guess. (I still prefer the socket in the boiler)   Also the plug between the tender and the loco is small and fragile. It would be easy to break it inserting it, it is difficulte to insert it evenly, and removing it requires pulling on the wires, which will eventually damage the connector.  

SUGGESTION TO ARISTO-CRAFT: ADD 2 MORE WIRES TO THE PLUG/SOCKET, WIRE THE CAB, MARKER AND NUMBER BOARDS SEPARATELY FROM THE HEADLIGHT. INCREASE THE SIZE OF THE CONNECTOR AND ADD "MEAT" TO ALLOW INSERTION AND REMOVAL BY PULLING ON THE CONNECTOR, NOT THE WIRES   Connecting sound:   Yes, it ran quietly, and I did not connect the sound jumper from the QSI to the Aristo electronics. In fact WHERE is the speaker connector? Hmm, there are 3 connectors UNDER the tender top, jeeze! How dumb is that? Now this is worse because the board is so high in the tender, you don't have a chance to get in there with your fingers. They are about one inch back from the opening. WARNING: before working on the tender, notice on the fireman's side there are 4 small, fragile "hooks" on the lower edge of the tender. If you lay the tender on this side, you are likely to break them. Off comes the tender shell... stupid... 6 screws.... now you can see the connectors... read that on/off switch again, no telling what it does.   whoops, there is the wire to the backup light, look carefully, it has a connector you can disconnect, usually tucked around the speaker. Interestingly the connector is polarized. This will come in handy if you replace the bulb with a LED.   OK, it works. The speaker looks pretty similar to the standard Aristo one, but will measure to be sure.   For a $540 loco, it would be nice to get the connectors with the loco...   I noticed 2 more connectors, and these are NOT documented in the manual. One apparently is fixed, and the other variable. I assume one is power for a sound board and the other is for the sound board to "read" the voltage to the motor.     Couplers Also of interest, the tender has a tang for truck mounting of a coupler, but no coupler was mounted. As mentioned earlier, there are 2 loop couplers and 2 Arist knuckle couplers provided. I'll most likely body mount a Kadee coupler to the tender.

CONSOLIDATION PARTS

P20601-12 R.CYLINDER EXHAUST
P20601-15 SMOKE BOX FRONT
P20601-17 TOP DOOR HINGE
P20601-25 LH FRONT STEP
P20601-29 RH SHAFT LEVER
P20601-33 R.STEAM PIPE
P20601-37 RH AIR TANK
P20601-47 HEADLIGHT LENS
P20601-51 RH CAB WINDOW
P20601-53 MARKER LIGHT LENS
P20601-65 CAB SUPPORT
P20601-69 REAR STEAM PIPE
P20601-79 L.PISTON ROD
P20601-89 HEAD LIGHT
P20601-04 REAR CYLINDER
P20601-06 CYLINDER EXHAUST
P20601-08 CYLINDER SUPPORT
P20601-16 SMOKE BOX DOOR
P20601-18 BOTTOM DOOR HINGE
P20601-22 HEADLIGHT PLATFORM
P20601-24 CYLINDER SUPPORT
P20601-26 RH FRONT STEP
P20601-48 HEADLIGHT SIDE LENS
P20601-62 RADIUS ROD
P20601-66 DRAW BAR MOUNT
P20601-68 SUN SHADE
P20601-80 PISTON ROD
P20601-82 GENERATOR
P20601-84 MARKER LIGHT
P20601-90 PILOT TRUCK MOUNT
P20601-91 PILOT TRUCK RETAINER
P20601-101 CHASSIS ORNAMENT
P20601-111 STANCHION
P20601-92 PILOT
P20601-146 FLY WHEEL
P20601-64 PILOT SUPPORT
P20601-96 MARKER LIGHT SCREW
P20601-22 TENDER WHEEL B
P20601-05 COAL LOAD
P20601-01 SUNBEAM HEADLIGHT
P20601-02 NUMBER PLATE GLASS
P20601-07 SUNBEAM REAR LIGHT
P20601-12 TENDER LADDER
P20601-10 TENDER STEP L
P20601-111 TENDER STEP R

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Aristo EMD GP40

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Overview:

A recent loco, following the new Aristo-Craft policy of smaller locos for tighter curves.

Santa Fe only had one of these, and the model has the correct road number. It's a good looking loco, with the standard Aristo "prime mover" gearbox system, except for new motors (more later).

But, after about a year of use, many people have reporting many different problems. The coupler problem was obvious right away. In early 2009, I noticed many posts about failing plating on the wheels. Since Aristo diesel wheels are steel, they will rust and pit quickly, bad power pickup.

In late 2009, there were several reports of the motors literally going up in smoke. The common symptom is the motors start drawing a lot more current than normal, and heat up and smoke. The evidence points to counterfeit motors with poor quality insulation on the motor windings, that is not the proper high temperature enamel, but a cheaper lookalike.

Ted has posted a video that shows one loco drawing 2 amps at 5 volts, and the loco is on rollers! (That is way too much).

Axel Tillman of Train-Li, whose motorized switch machine Aristo-Craft so blatantly copied, noticed this inferior insulation on the Aristo motor in their switch motor clone.

First run (and problems):

This is the first loco made for Aristo-Craft in the "new" Sanda Kan factory. (This was just before Kader bought Sanda Kan). I believe this is the reason for many of the flaws in this loco.

One small detail, there are 2 small holes above the couplers where the MU cable should emerge. The first run did not use these holes, the cable comes out underneath the shell. It's very common for it to drop down, and catch on parts of a switch and get torn off.

Quite a few people have reported couplers "coming apart" on the GP40 where the identical train on another Aristo-Craft loco is fine. It appears that the batch of couplers either have greater knuckle flex, or possibly the castings have "shrunk" more than usual. In any case it's true, and it's the couplers sliding apart sideways, not the knuckles popping open!

In late 2009, I started getting reports of the loco's "burning up". There's now many documented cases of the motors themselves drawing excessive current. In severe cases smoke has come from them.

It sounds like there may be a "lifetime" issues with these motors. Will keep you informed, but if you buy a used GP-40, be sure to watch out for this.

Subsequently, Aristo-Craft has publicly announced they have 1000 replacement motors in stock. Draw whatever inferences you want to, no one get's 1000 "spare" motors.

Be sure to read Ted's vignette on the motor problems and solutions: Ted's Vignette on GP 40 motors

Second run:

Even though marked 2008 on the body shells, there seems to be a variation. The mu cables now come out of the holes in the body shell as it was obviously designed.

Also, the motors appear different. Ed Headington reports that a loco he purchased in December 2011, you no longer can see the cooling fan in the motor "vent hole". There are openings in the motors, but there is no fan visible. This may be a helpful spotting guide, I need more people to confirm these differences.

Electrical considerations:

This loco has a ton of polyswitches. It appears that they are in the battery buss ("mu cable") and on the main board. If you run heavy loads, or use the mu cables to run more than one loco, you will most likely have to bypass these. As always try to protect from shorts. This means an intelligent rewire. In a perfect world, on each of the pickup wires from the trucks would be best, along with one of the leads to the main board, but it's your choice.

Here are some pictures of the circuit boards inside, courtesy of John Burden:

Below is the main board top, with the switches visible:

Below is the same board, but from the underside, you can see the Aristo socket: (the dummy plug is still in the left hand socket)

There are 2 more circuit boards, one in the front:
(notice the 4 pin plug on the right, that comes from the motor block)

There is likewise another circuit board in the rear, see the picture below:

The motor blocks have the 4 wire cable coming from them, as shown below: (following pictures courtesy of R.J. DeBerg)

The 4 wire cable connects to a small pcb, unlike the 6 axle diesels. That pcb is wired to the motor, and gets the power pickup from pressing against the metal wires in the top of the motor block:

 I don't think a lot of this connection to the power pickups, there is no spring contact to touch against the circuit board. It's wise to check your power pickup to each block when you get your GP40, you might only be picking up from a few "sides". A dab of grease in here will keep the connection better. Notice the metal "finger" on the bus wire, aligned with the axle? This is the metal strap that goes down inside the motor block to contact the gearbox. This is a potential source of problems. In the Aristo steamers, this connection is now soldered from the factory. If you solder this one though, you run the risk of interfering with the contact the circuit board makes. If you were careful, and made a nice smooth solder blob, it actually might help for 2 reasons, ensuring the metal clip is connected very well to the bus wire, and also providing a high point to better press against the circuit board.

The picture below is out of focus, but you can make out the part of the circuit board where the contact is made:

More on the motors:

Paul Norton, beloved "son" of Aristo even posted the problems he had on the Aristo site, and got replacement motors and they are slightly longer. This reinforces my "counterfeit motor" theory, and that Aristo was duped:  http://www.aristocraftforum.com/viewtopic.php?t=16598

"Well things did not go well. It turns out the new motor casings are 1/16 of an inch longer than the originals. The problem was solved by shaving the two small ridges off the back of the motor cavity in the first motor block. The motor now fit, but would rock sideways. The motor in the unmodified motor block was checked and it rocked, but not to the same degree. A couple of shims (0.030” thick, x .0.25” wide x 0.49” long) were glued to the front of the motor block cavity for the motor terminals to sit on."

The GP-40 reportedly uses a Mabuchi 545 motor with a fan, but other observations indicate the logo on the stock motors looks "funny".

Kadees:

Even though the Kadee site gives different recommendations, I suggest that you read Ted's vignette for installation, and a better solution in my opinion.

Wheel plating quality:

Many people have commented on the poor quality of the wheel plating. Since the underlying metal is steel, pitting and rust can be a big problem on track power and/or moist climates. Some reports have had the plating come off in as little as 5 hours. This is probably another problem with the "new" Sanda Kan factory.

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