Many trains in Japan are not MUs—rather, they are the usual sort of locomotive-hauled affair more common in the rest of the world. These days, most locomotive-hauled trains are freight trains, but a good many Sleeper Expresses (”Blue Trains”) and special-even trains are still pulled by locomotives.
Kato now makes nearly all of its model locomotives DCC ready, in that installation requires little more than the replacement of an existing lightboard. In this article, I focus on these models. In a future article, I will discuss the remainder of the N-gauge model locomotives on the market, those that are not DCC ready.
JR Freight EF64 1024
In this article, I explore the options available to the Japanese rail modeler for using DCC to control the lights and movement of Kato DCC ready locomotives.
Kato uses three kinds of lightboards in their designs, which I have labeled “Narrow”, “Wide”, and “Short”, for lack of better terms. The narrow-style board is extremely common in their North American outline models, but it is only used in one Japanese model, the DD51—all of these are rather narrow diesel locomotives. The short-style is relatively new, showing up in the North America NW-2 switcher, and a new release of the C62 steam engine. I suspect that the upcoming DE10 release may use this board as well. (I have just been informed by an owner of the new DE10 that it takes the “Narrow” style board. Photos.) The wide-style board is used extensively in everything else (including some European HST locomotives).
Wide
DF50 DF200
EF58 EF60
EF63 EF64
EF65 EF66
EF81 EF200
EF210 EF510
EH200 EH500
ED75 ED79
E851
Narrow
DD51 DE10
Short
C62 DE10
The Perfect Locomotive Decoder
The perfect locomotive decoder would have the following properties:
- 2-functions—Kato DCC ready locomotives have functional headlights at both ends of the locomotive. A drop-in decoder should replicate the two light functions on the lightboard it replaces. Some of the decoders listed in this review require the user to install one of the lamps themselves, or alter the length of an installed lamp, but all reviewed decoders offer at least a two functions, usually F0f and F0r.
- Directional lighting—The headlights should alternate automatically depending on the direction of travel.
The perfect locomotive decoder might have one or more of the following properties, depending on the model and desires of the modeler:
- 4 or more functions—Although Kato locomotives do not have markerlights installed at the factory, they do provide lightpipes for those of us adventurous enough to add the lamps ourselves. Typically, four 1mm or SMD LEDs are needed—two at each end of the train. Thus, each function output should be able to handle two LEDs either in parallel or in series. If a decoder offers six or more functions, you can achieve a greater variety of effects by connecting the markerlights to multiple function outputs simultaneously. Finally, in the C62 steam locomotive, an extra function can be used to simulate a lit firebox.
- Headlight dimming—Japanese trains dim their headlights when passing through or standing at passenger stations.
- Smooth Movement—Since Kato DCC ready locomotives are all equipped with flywheels, and are very smooth runners from the factor, Momentum and BEMF control are less important for achieving smooth and realistic operation. Nevertheless, every little bit helps.
- Advanced Consisting—Although consisting locomotives is uncommon in Japan, it is not rare. For example, trains—locomotive hauled and EMU alike—passing through the Usui pass (before that section of track was shut down) would consist with a pair of EF63 helper locomotives. Passenger trains in Hokkaido are often pulled by a matched pair of DD51s. Trains passing through the Seikan tunnel are pulled by a pair of EF79s.
- Fancy Momentum—Some modelers prefer to have more fine-grained control over momentum features, such as a tunable momentum curve, or a programmable constant-stop distance (very handy for accurate automated station stops).
- Bidirectional support—Some users seek to automate their layouts, to some degree, and such automation often requires (or is at least enhanced by) bidirectional communications, either Digitrax’s proprietary Transponding, or NMRA RailCom.
| Short | Wide | Narrow | |||||||
|---|---|---|---|---|---|---|---|---|---|
| DN123K3 | K3D3 | #0001664 | N12K0a | DN163K0a | K0D8 | #0001642 | K1D4 | DN163K1d | |
| Manufacturer | Digitrax | TCS | MRC | NCE | Digitrax | TCS | MRC | TCS | Digitrax |
| Rating | ★★☆☆ | ★★★☆ | ★☆☆☆ | ★★☆☆ | ★★★½ | ★★★★ | ★☆☆☆ | ★★★☆ | ★★★½ |
| Price | $30 | $35 | $35 | $30 | $35 | $40 | $35 | $35 | $36 |
| Price per Star | $15 | $12 | $35 | $15 | $10 | $10 | $35 | $12 | $10 |
| Recommended? | ✓ | ✓ | ✓ | ✓ | ✓ | ||||
| Functions | 2 | 3 | 2 | 2 | 6 | 8 | 2 | 4 | 6 |
| Advanced Consisting? | ◯ | ◯ | ◯ | ◯ | ◯ | ◯ | ◯ | ◯ | ◯ |
| Loadable Speed Table? | ◯ | ◯ | ✕ | ◯ | ◯ | ◯ | ✕ | ◯ | ◯ |
| Dimmable Lights? | △ | ◯ | ✕ | ◯ | △ | ◯ | ✕ | ◯ | △ |
| BEMF? | ◯ | ◯ | ✕ | ✕ | ◯ | ◯ | ✕ | ◯ | ◯ |
| Fancy Momentum? | ✕ | ◯ | ✕ | ✕ | ✕ | ◯ | ✕ | ◯ | ✕ |
| Transponding? | ◯ | ✕ | ✕ | ✕ | ◯ | ✕ | ✕ | ✕ | ◯ |
| RailCom? | ✕ | ✕ | ✕ | ✕ | ✕ | ◯ | ✕ | ✕ | ✕ |
| Max Current (cont. func.) | n/a | ? | n/a | n/a | 500 | 60 | n/a | 50 | 500 |
| Max Current (peak func.) | n/a | ? | n/a | n/a | ? | ? | n/a | ? | ? |
| Max Current (cont. total) | 1250 | 1000 | 1000 | 1000 | 1500 | 1000 | 1000 | 1000 | 1000 |
| Max Current (peak total) | 2000 | 2000 | ? | 1250 | 2000 | 2000 | ? | 2000 | 1250 |
Reviews
Digitrax DN123K3
The DN123K3 is a replacement for the Short Lightboard, currently only used by C62 steam locomotives (among Japanese outline models). The decoder was designed specifically for the Kato NW-2, and therefore offers no additional lighting functions, which precludes modeling a lit firebox. Nevertheless, as with all recent Digitrax decoders, the feature set is fairly robust, including Transponding and BEMF. But Digitrax’s implementation of Rule 17 lighting is not as flexible as other manufacturers.
Summary: A good feature set, and a modest price. If you require Transponding, this is your only option.
Links: Digitrax website, DN123K3 manual.
TCS K3D3
The K3D3 is, like its Digitrax counterpart, designed explicitly for the Kato NW-2. Unlike the Digitrax offering, the K3D3 offers a third function output, which is perfect for simulating a lit firebox. Interestingly, TCS has built a resistor for the third function directly into the board, so that you can wire an LED directly to the function output. The feature set is otherwise comparable to the Digitrax decoder, offering more finely-tuned momentum and headlight dimming settings but no bidirectional support.
Summary: Although it is slightly more expensive than its Digitrax counterpart, the larger feature set rates this decoder a recommendation.
Links: TCS website, K3D3 manual.
TCS K0D8
TCS only recently announced this decoder for a mid-October 2009 release. This decoder has 8 (!!) functions—more than ample for the Japanese model railroader. Two of the functions are taken up by on-board LEDs; four have built-in resistors for LEDs or 1.5V bulbs; two run at the full 12V. There are actually four variants of this decoder, each with different length and number of installed LEDs to fit different locomotives. The ‘A’ variant has two long-leaded LEDs; the ‘B’ variant has a single medium-leaded LED; the ‘C’ variant has two short-leaded LEDs; the ‘D’ variant has no on-board LEDs. Although not yet confirmed, this new decoder will likely also support RailCom, as several of TCS’s recent releases now have RailCom support.
Links: TCS website, K0D8 page with links to manuals.
MRC #0001664
MRC’s forte is making sound decoders, and although they make sound decoders that fit the Kato “wide” lightboard profile, all are aimed at North American diesels, and so none are appropriate for Japanese electrics. Once you take away the sound functions, though, there isn’t much left to this decoder: Two functions and support for advanced consisting are the only features this decoder offers. That said, there is nothing lacking in the awkwardly-named #0001664—it is adequate for Japanese-outline locomotives, but only just.
Summary: With a price in line with the competition, but with only a fraction of the feature set, you could do a lot better.
Links: MRC website, #0001664 manual.
NCE N12K0a
NCE’s N12K0a is a considerable step up from the similar MRC decoder, offering the addition of dimmable headlights and a 28-step speed table. Unlike either of the other offerings, the N12K0a comes with only one LED fitted; you will have to supply the second LED. This is actually something of a blessing, because typically the leads on the LEDs provided in these decoders are too long to fit inside the shorter Japanese outline shells. Thus, the N12K0a only requires desoldering one LED (though you must still trim two, and indeed, have a second one handy in the first place). The NCE offering has the further advantage of being less expensive than either of the other offerings for “wide” lightboards.
Summary: A modest price, but also a modest feature set.
Links: NCE website, N12K0a manual.
Digitrax DN163K0a
Compared to the competition, Digitrax’s DN163k0a packs in a ton of features, and six (six!) functions. As the only “wide” style decoder offering more than two functions, the DN163K0a is the only option if you want working markerlights on your model. As with all other recent Digitrax offerings, the DN163K0a offers Transponding and BEMF, but Digitrax’s implementation of Rule 17 lighting is not as flexible as other manufacturers.
Summary: A very good feature set (especially compared to the competition) at no additional cost. Recommended.
Links: Digitrax website, DN163K0a manual.
MRC #0001642
MRC’s forte is making sound decoders, and although they make sound decoders that fit the Kato “narrow” lightboard profile, all are aimed at North American diesel-electric locomotives, and so are likely inappropriate for DD51, because it is a diesel-hydraulic. Once you take away the sound functions, though, there isn’t much left to this decoder: Two functions and support for advanced consisting are the only features this decoder offers. That said, there is nothing lacking in the awkwardly-named #0001642—it is adequate for Japanese-outline locomotives, but only just.
Summary: With a price in line with the competition, but with only a fraction of the feature set, you could do a lot better.
Links: MRC website, #0001642 manual.
TCS K1D4
Unlike the MRC offering, the K1D4 packs quite a few features into the very narrow confines of the “narrow” lightboard profile, including BEMF, finely-tuned momentum, and headlight dimming settings. Of particular interest are the two additional functions. These functions have resistors already wired in place to ease the connection of 1.5V LEDs. However, because Kato does not provide lightpipes for the markerlights (just red lenses), you need one LED per lens to get properly bright markerlights. As a result the 50mA maximum current per function is really too low to power two LEDs. Nevertheless, the option is there, which is far more than can be said for many decoders in this review.
Summary: Fully-featured, and modestly priced. Recommended.
Links: TCS website, K1D4 manual.
Digitrax DN163K1d
Compared to some of the competition, Digitrax’s DN163k1d packs in a ton of features, and six (six!) functions. As with all other recent Digitrax offerings, the DN163K0a offers the full spectrum of features, including Transponding, but Digitrax’s implementation of Rule 17 lighting is not as flexible as other manufacturers.
Summary: A very good feature set at minimal additional cost. Recommended.
Links: Digitrax website, DN163K1d manual.
Boring Explanations
Stars
A decoder’s rating is calculated by considering equally the number of desirable features offered, and the number of functions offered. Price is not used to computer the rating.
☆☆☆☆ Do not use. Unsuitable.
★☆☆☆ Adequate. Suitable, but you could do better.
★★☆☆ Fine. Suitable. Often will have the best feature set for the least price.
★★★☆ Good. Well suited. Has more or better features than most.
★★★★ Perfect! An ideal decoder. Has most or all of the best features, but is often also the most expensive.
Price per Star
This is the ratio of the decoder’s price to it’s rating in stars. The number is a rough guide to the cost-to-benfit ratio. Lower numbers represent a better cost-to-benefit ratio; higher numbers represent a worse cost-to-benefit ratio.
Functions
Two functions are the minimum: One for each set of headlights. Two more functions are even better: One for each set of markerlights. Of course, the Kato locomotives that these decoders will fit don’t actually come with markerlights, but they do come with clear red lenses and space to fit a small LED. Some frame milling may be required, but nothing extensive. Two more features and…well, I’m not sure what those buy you. I don’t see any reason why you could wire the markerlights to two function outputs simultaneously to allow a broader range of effects.
Advanced Consisting
If you want to consist locomotives, Advanced Consisting is the way to do it. The hard way is to assign each locomotive in the consist the same address, but then you cannot operate their various lights prototypically—each locomotive will have its headlights on, for example! Advanced Consisting allows each locomotive to keep its individual address by adding a secondary address. Consisting is only activated when an address is programmed into this secondary slot. Moreover, decoders with Advanced Consisting give you the option of setting up alternate programs for the various functions, allow prototypically-correct lighting control during consisted operation. If you are going to consist a locomotive or two with an EMU or DMU, make sure that the decoders you use in the MU also support Advanced Consisting.
Loadable Speed Table
All decoders today support the three-step speed table. This table maps voltages two the lowest non-zero throttle setting, the middle throttle setting, and the highest throttle setting. But many locomotive models do not have a linear response to increased voltage, and indeed, neither do the prototypes. A 28-step speed table, also called a loadable speed table, divides the throttle into 28 regions (instead of just three), giving you more control over the models response to throttle changes.
Dimmable Headlights
As in the United States, Japanese rules of operation require trains to dim their headlights when passing or standing at passenger stations. Although a subtle feature, many modelers enjoy prototypical lighting effects in their trains. Typically, a decoder that supports this feature will dim the lights when F4 is pressed. Any function decoder that supports “Rule 17″ operation of the lights will support this feature.
Digitrax’s implementation of Rule 17 lighting is not as flexible as other manufacturers. One option for Rule 17 lighting is to dim the headlight opposite the direction of travel, so both headlights are on. This is called “opposite dim” by Digitrax and TCS, and is not prototypical for Japanese locomotive operations. Unfortunately, Digitrax decoders do not allow you to disable this aspect of Rule 17 operation—headlight dimming and opposite dim are all-or-none in Digitrax decoders.
BEMF
Back EMF (BEMF) is a method for regulating the motor speed for smooth low-speed operation, and maintaining constant speed up and down inclines. It works by inferring the motor’s speed by measuring the amount of feedback generated by its rotation—called back EMF—and adjusting the voltage up or down to maintain a constant speed. This feature is critical for low-speed operations, including smooth acceleration and deceleration from and to a full stop.
Fancy Momentum
All the decoders surveyed offer basic linear acceleration and deceleration, but some manufacturers go a step further. TCS offers 3-step acceleration and deceleration curves for non-linear momentum. This feature is nice for simulating smooth and realistic-looking station stops and starts.
Lenz and ESU offer a feature called “constant stopping distance”, which, when active, varies the deceleration term to bring the model to a stop within a fixed distance, regardless of the speed of the model. This is great for automating station stops, because you will know the distance from the station throat to the stopping point, but you might now know just how fast a model is traveling when it enters the station throat.
Bidirectional Communications
RailCom and Transponding are two different systems of bidirectional communications over DCC. Normally, DCC is a one-way signal: From the command-station to the decoder. There is normally no method for DCC decoders to respond. RailCom and Transponding are methods for the decoder to send a response to the command-station. This is really useful for automated control of a layout, but is not a necessary feature to implement basic block occupancy detection, although both methods require a block occupancy detector detector to work. I won’t get into a discussion of the advantages or disadvantages of each system; you can read more about those elsewhere on the Internet.
RailCom is an open standard developed by Lenz and adopted by the NMRA as a Recommended Practice for DCC. That is, it is now an official, if optional, part of the DCC specifications. RailCom responses can be detected by a Lenz LRC130 RailCom detectors and reported to a computer via the Lenz LRC135 RailComBus USB adapter.
Transponding is Digitrax’s proprietary standard for bidirectional communication, and is currently only implemented in Digitrax decoders and Kato decoders designed by Digitrax. Transponding responses are detected by a Digitrax RX4 detectors, which must themselves be attached to a Digitrax BDL168 block occupancy detector. Transponding events can be communicated to a computer via the Digitrax PR3 LocoNet USB adapter.
Maximum Current Ratings
The current rating of a decoder tells you the largest load you can connect to the decoder. Each light, motor, speaker, etc., draws a certain amount of current; attaching too many will cause the decoder to overheat and perhaps even die.
A manufacturer often lists two or more different current ratings. A current rating is either for each function individually, or the total current for all functions combined. Moreover, a current rating is either a continuous rating or peak rating.
Continuous Current per Function is the amount of current a decoder function lead can handle over an indefinite time period. For example, if the literature claims a 125mA continuous function current rating, then you can attach a lamp that draws up to 125mA to that function, and leave it on as long as you please.
Peak Current per Function is the amount of current a decoder function lead can handle for short bursts. Incandescent lamps, when they first turn on, have an inrush current that is ten times the current draw of that lamp. For example, a lamp that is rated as drawing 50mA will actually draw 500mA very briefly when it is turned on. So this rating is important to know when you are using incandescent lamps. LEDs do not have a significant inrush current.
Continuous Total Current is the total amount of current that the decoder can supply for all functions combined over an indefinite time period. The sum of the current draw of all lamps must not exceed this amount. This may limit the number of lamps or other loads you can attach to the decoder.
Peak Total Current is the total amount of current that the the decoder can supply for all functions combined for short bursts. This is particularly important for motor decoders, where the stall current of the motor (the amount of current the motor draws when it is stalled or locks-up) must be less than this number. Unless you will be using a large number of incandescent lamps (see above), this number is relatively unimportant for function decoders.