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Aristo C-16 Tips

Aristo C-16 Tips

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The information presented below is substantially based on ONE PRE-PRODUCTION C-16 so that some of the things that I observed may be particular to this individual unit. The paint scheme on this unit differs from the "production" paint scheme that I saw at the 1999 Big Train Show at the Queen Mary.


The C-16

The C-16 is a small steam loco commonly called a Consolidation type, or 2-8-0. The C-16 class itself was pretty much exclusively used on the D&RG in their early days, but the Consolidation type was used everywhere in great numbers through the last part of the 19th century. Even into the 20th Century, the Consolidation type continued to be built, but generally in larger configurations than the C-16. With some minor detail work, the Aristo C-16 could pass for a PRR Class H1 type, or a narrow gauge version of many other kinds of Consolidations that ran all over the country.

This model is a remake of the original Delton C-16. Aristo purchased the molds and the model, according to Aristo, should look very similar to the Delton product in most aspects, including most proportions. Aristo has entirely rebuilt the mechanism as the original Delton mechanism had a nasty reputation for poor performance and reliability. The major change is that the gearbox is now dicast metal and the first and fourth drivers are driven by gearing. The gearbox was also designed so that "daylight" still shows under the boiler forward of the firebox. Unfortunately, there wasn't room for adequate gearing so the engine body was raised by 1/4" to make room. This made the model deviate from the exact proportions of a real C-16. Finescalers are outraged by this change, but in this case the reality of product design outweighed finescale concerns. However, this "problem" can be fixed with a little bashing on the model, see Lowering the C-16 below.

Aristo paints and details the engines in various schemes, some as coal burners, some as wood burners. Details such as stacks, marker lights, pilots, compressors, air tanks, dynamos, headlights, domes and such will vary from model to model.

atsf c-16The ATSF model pictured is a wood burner which is representative of a Baldwin or Grant catalog engine. It has a very long pilot, a diamond stack to catch cinders, fluted domes, a single stage air compressor, a kerosene headlight (therefore no dynamo either) and no marker lights. This is a pre-production unit and Aristo says that the paint scheme will be "fixed" on production units although I don't see much wrong with it from a general point of view. I have no photos of a very early ATSF 2-8-0 to check the "accuracy" of the paint scheme. The scheme does not represent engines that were painted 50 years later, but things could have changed in half a century. The engine is numbered 18 on the engine and tender body, but has a number of 268 on the smokebox door.

Most of the gold colored details including the pops, whistle, headlight bezel, domes caps, cylinder heads and such on the wood burner are turned brass parts. The handrails and piping are brass rod. The bell is painted dicast metal. The connecting rods are plastic.

Mac's DGRW C-16The Denver and Rio Grand Western model pictured here is a more modern coal burner that represents the real C-16 type. The pilot is shorter, it has an electric headlight and a dynamo, non-fluted domes and dual air compressors. Please note that this is also a pre-production model. Further Mac McCalla has already had at this one. Mac has lightly (by his usual standards) weathered it and some of the details that were on the original model have been moved, modified or changed out entirely.


Performance and Overall Impressions

The ATSF Aristo C-16 that I evaluated runs very well and pulls strongly. It handled 12 heavy cars with metal wheels on a 1.6% grade. See my Tractive Effort Tests page for the details. This engine pulls the most cars for the least current of any engine that I have come across so far so it would be a good candidate for battery power. In testing on the indoor GIRR, Mountain Division, it would handle 8 cars with metal wheels on a 4.2% curving grade and 4 cars in a 5.2% 4' diameter spiral.

The center two drivers are blind (no flange). This not only aids in getting through tight curves, it is prototypical as the real C-16's had blind drivers. Unlike the Aristo Pacific and 0-4-0, the driver axles are not allowed to rock with respect to one another. This will tend to make the engine more sensitive to poorly leveled track, but it also allows the engine to slip gracefully when overloaded. The Aristo Pacific and 0-4-0 hop about and complain loudly when they start to slip.

There was some gear noise at first, but it quieted down considerably in only a few minutes of running and then continued at the "light whine" level. The engine runs smoothly at low speed, although it takes a little higher track voltage to start moving than a Bachmann Shay. This is not a fast engine, it more closely matches the speed of the Shay than any of the other Aristo engines. I was successful in double heading the C-16 and the Shay. At speeds up to about 15 smph (the fastest that a real Shay would go) it matches the speed of the Shay quite closely. At 18 volts, I estimate that the C-16 runs at about 30 smph, about the top speed of a real C-16.

After a week, I've had the opportunity to put some hours on the engine. I estimate that I've got about 20 hours on it so far, with about half of those under maximum load. Under extended running with all the cars it will pull on the grades of the outdoor GIRR (12 cars in that case) the gearbox got warm but the engine showed no signs of stress.

The engine is already fairly heavily weighted so that I imagine that there is not much room in the boiler for anything else. The tender is small too so fitting it with onboard batteries would be a challenge. However since the engine only draws a little over an amp with a maximum practical load, a small battery set may work.

The engine is equipped with a smoke unit, and in typical Aristo fashion, it smokes for quite a while, but not real strongly. There is a three position toggle switch on the backhead which allows the engine to run with the motor, lights and smoke, with just the lights and the motor or with lights only. There does not appear to be a way to turn the lights off although this may be a pre-production problem as the instructions indicate that the lights should go off. The engine is not equipped with a sound system but after market systems can easily be installed.

The headlight is bright and white and casts a good beam although it is not directional. There is also a light in the firebox, but it does not flicker. I do not know if the models with markers have illuminated markers.

I laid some 2' radius track and turnouts on the family room floor to see how it would do. The bottom line is that it did fine. Even though it has a longer wheelbase, it doesn't complain in a 2' turn like an LGB Mogul. The engine is smaller than a Bachmann Big Hauler, so anywhere a Big Hauler will go, the C-16 will go too.

When I took the C-16 to the indoor GIRR, Mountain Division, it ran fine too and fit everywhere that the Big Hauler did. However, a couple of times the lead truck on the tender derailed. I suspected a problem with the drawbar, see the Problems section below for details.

The drawbar design is different that other Aristo locos and I think that it is generally better. Unlike the design on the Aristo Pacific (which is a major pain in the backside to connect or disconnect) it is easy to get the engine and tender connected, and when the drawbar finally latches under the tender, there is a reassuring click. I have had no difficulty with the drawbar separating, even under very heavy loads.



I initially experienced no derailment problems on my outdoor track (which is not in the best condition courtesy of El Nino) although there was an easily correctable interference issue, see the Problems section below.

Later, when I was running with a heavy load on a little used section of track, I noticed a consistent derailment difficulty. As the engine exited a curve, it would consistently derail on a turnout. As turns out, the pony truck was derailing halfway through the curve and then kicking the engine off the track when the already derailed pony truck hit the turnout. I found that this section of track changed from a positive superelevation of about one bubble, to a negative superelevation of about a bubble, back to a positive superelevation of about a bubble, all within about one foot! This was too much for the engine to handle. When the track was set for a consistent superelevation, the engine had no more difficulties on this section.

However, running the other direction I began to have a problem on one spot that is under construction where the track is not adequately supported. Here, I found another systematic derailment difficulty. It is true that this is a pathological case, but this time I decided to see if I could make the engine more tolerant instead of fixing the track. I did find that a simple modification to the pony truck mount allowed the engine to pass this section without difficulty and without fixing the track (it'll get the track fixed later when I am finished with the roadbed in that stretch).

When the track changes in level abruptly, the engine body can tip and lift a pony truck wheel off the track. The pony truck can then move sideways and when it comes down, it can be off the track. The engine can actually run for quite a distance with the pony truck derailed without seeming to have a problem. I discovered by inspection that the vertical travel of the pony truck was limited by an interference between the truck pivot and the engine gearbox. This limits the ability of the pony truck to drop downward far enough to stay on badly leveled track.

modified pony truckI ground off some plastic from the rear of the pony truck pivot where it was binding against the gearbox. This binding was fairly severe as the paint had been rubbed off the metal gearbox at that location. I kept grinding and fitting until light started to show through the plastic indicating that I had removed nearly all of the plastic right at the top of the pivot. I also reinstalled the pivot without tightening the mounting screw all the way down. Now the pony truck has significantly more vertical play and moves MUCH more freely AND the engine will run by the especially bad track without the pony truck wheels lifting at all and without derailing.


Scale and Size

c-16 vs shayThe C-16 is a fairly small engine, built to 1/24 scale. 1/24 scale is not correct for the 3' narrow gauge C-16 prototype (1/20.3 is the right scale) so the engine will look a little small against other 1/20.3 scale equipment. Sitting next to a 1/20.3 scale model of a 36 ton Shay, the C-16 is visibly smaller. The 36 ton Shay is a small engine too, in real life they would be about the same size.

c-16 vs big haulerEven sitting next to a Bachmann Big Hauler the C-16 looks small. The boiler sits much lower and the cab is lower too. The Ten Wheeler prototype was not a large engine either, but it was intended for higher speeds and had taller drivers. The C-16 was intended to haul freight at low speed and had especially small drivers so that eight of them could fit under the engine. However, compared to the Bachmann stock car behind the C-16, the proportion is good.

I don't have a set of C-16 drawings so I couldn't check the engine for accuracy. If someone out there has access to some drawings, I'd like to get a copy so that I can measure the engine against them.

The wood burner C-16 with the diamond stack is 6-7/8" tall over the railheads, 4-1/2" wide over the cab roof and 25" long over the extended pilot to the rear of the tender deck. The worst outside overhang is at the rear corner of the cab roof at 2-7/8" from the track centerline on 2' radius track. The worst inside overhang is less than that of a typical boxcar. This is small enough so that it will probably fit on most layouts.


Power Pickup

Power is picked up on all eight drivers and four tender wheels. On my unit, one of the drivers on the third axle didn't pick up power, but this is not really a big deal because the blind drivers don't sit on the track all the time anyway. The pony truck has metal wheels but does not pick up power. There is a small electrical connector between the engine and tender that gave me some minor grief, see Problems below.

The drivers have plastic centers with metal tires. Power is transferred from the tires to the axle by a metal clip. On my unit, this clip was not making electrical contact to the tire even though it visually appears to be in contact. Sometime, if I ever have to take the driver off, I'll fix it.

The tender wheels have metal tires on plastic centers. Power is picked up on four tender wheels with low drag replaceable carbon brushes.

The C-16 seems to tolerate moderately dirty track gracefully and the engine wheels do not seem to load up with crud as I have experienced with other Aristo steamers. The tender wheels do seem to get dirty faster than the engine wheels. Even with intermittent power pickup, the motor seems to be able to keep spinning so that it can coast over bad track such that the gear whine pitch changes some but the engine doesn't sputter or jerk like some other locos.

While playing with a digital sound system installed in the tender, I noticed that the tender wheel power pickups seem to have fairly high and unstable resistance ranging from 20 to 200+ ohms per wheel. The excessive resistance appears to be located at the interface between the wheel and the brush itself. The contact brush resistance itself varies a little, but is usually on the order of 2 ohms or so. Burnishing the blackening off of the backs of the wheels did improve the situation, but it was not a complete solution. The lowest resistance came down to the sub 10 ohm range, but the contact resistance would still go to several tens of ohms at times. These wheels are cast so that the backs are not completely smooth. This may be a contributor to the varying resistance.



The power connector between the engine and tender is arranged to hang out the back of the engine. However, in backing moves, it tended to get dragged underneath the engine and hang up in turnouts. I rerouted the connector and wire through the drawbar slot and used a small cable tie to anchor it to the side of the drawbar and that problem went away.

The drawbar itself clips under the tender. Besides the fact that mine was broken out of the box (some Zap-CA fixed that in a hurry) the drawbar tends to lift the front of the tender off the track slightly. This didn't give me any derailment problems on the outdoor layout. However, indoors I got a couple of derailments of the leading tender truck so the drawbar was immediately suspect.

drawbar photoThe drawbar seems to be 1/8" too high at the tender connection and it is also 1/8" thick. The fix was obvious. I broke the glue joint in the middle of the drawbar and reglued the end of the drawbar under the piece attached to the engine with a 1/4" overlap. This both lowered the drawbar by 1/8" AND pulled the tender closer to the engine by 1/4". In a 2' radius curve, the front corner of the tender deck just misses the engine frame. With the modified drawbar, the tender truck derailments ceased and I still had no problems with the drawbar disconnecting by itself.


Coupler Issues

As soon as I started to test the pulling power of the engine, I ran into a problem. The stock Delton type coupler is mounted too low to couple with the Kadee "G" Scale couplers that I use on the GIRR. Since the engine is eventually going to the GIRR, Mountain Division which uses LGB knuckles, I just hacked on a Kadee for testing.

I used a Kadee #831 by grinding out the Delton type pivot post and mounting the Kadee body with a Kadee screw to a hole that was already in the coupler mount. There are two bumps on the side of the #831 body that need to be ground off to allow the body to fit. Even so, the coupler is a little low. Grinding off some more of the coupler body would fix that. The coupler works OK mounted this way, but the coupler sticks out too far.

kadee on c-16 tenderCutting off some more of the coupler mount allows an #831 body to be tucked back under the tender where it belongs. I cut the side panels of the mount so that there was only about 1/4" left and then filed the remaining mounting surface flat.

modified lgb knuckleThe very end of the coupler body must be ground down so that it will fit under the axle when the truck springs are compressed.

lgb knuckle on c-16 tenderAn LGB knuckle coupler will mount the same way in the same hole that the tucked in Kadee uses. It also mounts a little low, but the LGB knuckle is very tolerant to incorrect mounting height. The end of the LGB knuckle also needs to be ground down to fit under the axle.

The pilot has too much overhang to reasonably expect a coupler to work there. The long pilot version has a nonfunctional drawbar on the pilot.


Lowering the C-16

David Fletcher provided a note on the LSOL and Aristo Bulletin boards with a description of how he lowered the C-16. It seemed the obvious way to do it and it turned out to be fairly easy. Virtually all of the modifications are done to the C-16 frame so it the conversion doesn't go well, another frame can be purchased and the engine returned to like new condition with one exception.

David's method is to hack at the frame such that the motor block recesses 1/4" higher into the frame. The mod does exactly what is necessary. The entire engine is lowered without significant impact on the air space between the frame and the boiler. There are some side effects, but they are minor.

c-16 before modificationThis is the C-16 before the modification. Note how high the pilot is above the track and how the pony truck has to reach down to the track. The centerline of the cylinder should line up with the axle, but is instead 1/4" higher.

c-16 after modificationAfter the modification, note that the pilot rides right down by the track, the pony truck is nearly horizontal and the cylinder centerline lines up with the axles. The motor block does invade slightly into the air space between the frame and the boiler, but only by about 1/16". The equalizer bars at the ends of the springs are disconnected from the frame, but this doesn't show much as they are hidden behind the wheels anyway.

c-16 motor blockThe C-16 motor block is a metal cased piece. It needs to be removed to do the work, but modification of the block is not required. The motor block attaches to the loco with a 4 terminal connector. The two center pins go to the motor, the outer pins to the power pickups. The block halves are electrically connected to the power pickups so there is an insulator between the case halves.

I checked mine and the motor and power pickup connections are isolated properly. However, there have been some reports that sometimes the motor is not isolated. I didn't tear into the block to look, but there might be cases of an unintended short between a motor terminal and a case half. If some future R/C or DCC installation is anticipated, this might be a good time to check it and fix it if there is a problem.

frame before modificationThis is the frame before any modifications. It has been stripped completely down. To get to this point, the superstructure is removed from the top, the motor block is pulled out of the bottom and the cylinder assembly is disassembled and removed from around the frame.

To strip the engine far enough to lower it, follow these steps. Your engine might be somewhat different as this unit is a pre-production model.

c-16 frame after modification The modification involves cutting and grinding on the frame and a couple of other pieces to allow the motor block to recess 1/4" more deeply. The bottom of the block will end up flush with the bottom of the frame.

Cut out the flat part of the frame under the boiler and grind it flush to the sidewalls. Then grind the forward part of the firebox 1/4" higher. Then grind each of the 8 axle slots 1/4" deeper. Keep grinding and fitting until the motor block fits easily and is completely flush with the bottom of the frame.

The springs are a bit of a problem when the equalization rods are ground to clear the raised motor block, they will be disconnected from the frame. The springs will then be attached only by the central support of each spring. Be careful not to break off the equalization rods. David commented that he cut the spring assemblies completely off and reattached them further outward so that they would clear the block. He also moved them 2 mm forward to more closely align them with the axle positions.

A new hole must be drilled for the motor block mounting screws between the 3rd and 4th drivers. Drill a new hole 1/4" above the old one.

This picture was taken before the frame was repainted to cover all the evidence of the grinding. The lower top surface of the motor block will need painting as well because it will stick up a little under the boiler.

c-16 cylinders before modificationThe center boiler saddle (the flat piece crosswise to the frame) also supports the crosshead and valve gear. This photo shows how it goes together before the modification. Since the motor block will partially invade the space that this part takes, it needs some relief ground in it to clear the raised motor block. Eventually it fits back in right where it is now.

c-16 cab bossesThere are also two bosses that stick out from under the cab. These will have to be ground off so that the original screw hole is completely gone or the bosses will interfere with the raised motor block. This is the one modification that is not easily reversible. David commented that he remanufactured new bosses that mount further rearwards, but I elected just to abandon them. The clips at the back seemed to be secure enough to hold the whole works together.

David noted a problem with the length of the piston rods. He had to trim his. Mine didn't interfere with the cylinder head so I left them alone. The crosshead will now move right up next to the cylinder, but it clears.

With the engine sitting lower, there might be a problem with the pilot. Mine hung just a little too low, the tip was exactly at the rail height and tended to catch on uncouplers and such. The pilot support rods can be used for what they were intended, to support the pilot. Raise the pilot by hand and observe how much of the rod sticks through the pilot. Then remove the rod and bend the bottom end backwards about 15 degrees for the length that stuck out when the pilot was at the right height. The bent ends will bind below the hole and you can then hook the top ends back into the smoke box to hold the pilot up.

The lowered engine frame also lowers the drawbar. Depending how yours sits now it might need some adjustment. In my case with the modified offset bar, I had to turn it over to raise the tender end of the bar to an appropriate height.


DCC Installation in the C-16

I haven't installed DCC in the C-16 as it currently resides at the GIRR, Mountain Division which does not use DCC. However, Ross Webster has written a page for his web site which describes his installation.



Smoke Unit Upgrade

The C-16 uses a standard Aristo type plug in smoke unit. The unit generates light smoke for quite a while, but often the density of the smoke is so light that at all but the highest speeds, it is not visible.

LGB or Seuthe elements work much better. If you can find a Seuthe unit, its the same thing, but probably cheaper. I choose an 18 volt unit as the C-16 runs the smoke unit directly from the track. At prototypical speeds, the smoke unit gets about 14 volts which is just right. The smoke unit generates very visible smoke but doesn't consume fluid at an inordinate rate. It also dissipates only about 1.5 watts which also seems about right for long life of the element, even running dry.

lgb smoke unit in c-16 stackAn LGB or Seuthe smoke unit fits right into the wood burner's stack with no modifications at all required to the loco. I do not know if the production wood burner stack or the coal burner stack will be so easy.

lgb smoke unit vs aristo smoke unitThe stock smoke unit plugs into the loco using a standard 3.5 mm miniature plug. All that is necessary is to trim the wires of the smoke unit to about 2" and solder them to the plug. The plug is then inserted into the loco and the wires are allowed to coil around in the base of the stack. These plugs are usually used for headphones and most will be set up for stereo with three connections, tip, ring and sleeve (in telco-speak). This one is a monaural version in that it does not have a "ring." Either kind will work, but don't connect anything to the "ring" contact.


Headlight Upgrade

The C-16 comes with a standard track powered, nondirectional incandescent headlight. It is fairly bright the way it is, but I elected to install a white LED in place of the bulb. More information on bright white LEDs can be found on my White LED Tips page.

stock c-16 headlight led c-16 headlight

The photo on the left is the stock headlight. The one on the right is after the white LED installation. In the photo, the LED doesn't look that much brighter, but it does cast a much better beam. Its color is more suited to an electric light instead the of the oil light on this version of the model but I like the brightness.

c-16 headlight circuitThe circuit diagram for the LED installation is very simple. A series resistor limits the current to the LED to about 15 mA. The extra diode is not really necessary but I put it in anyway. The LED is a diode itself so that it automatically provides directional lighting. However, I found little data on how well these LED's put up with reverse bias so I added the diode to prevent the LED from avalanching. I did test it without the diode and it appeared to work ok, no detectable current was drawn. When the motor is off, the LED will be absolutely dark when the track polarity is reversed. With the motor on, it LED will light dimly anyway. I assume that is because there is commutator noise that spikes the track voltage just a little positive, even going in reverse. If your LED lights brightly in reverse instead of forward, reverse the power wiring to the whole circuit.

c-16 headlight mountingThe physical installation in the C-16 is very easy. The headlight housing can be removed with two screws. Mine had a little bit of glue in there as well, but the headlight came off with minimal force. The hole in the bottom of the housing is big enough so that the LED can fit back through it. The diode and resistor mount in series with the LED leads and support the LED. The whole works is held in place with a dab of hot glue. The leads on the LED have to be bent close to the housing to allow the LED to mount rearward enough so that it doesn't interfere with the headlight lens.

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© 1998-2001 George Schreyer
Created 21 Aug 1998
Last Updated July 4, 2001