Some command control systems (previous to DCC) advertised forward and reverse speed steps combined - 128 speed steps would be 64 forward and 64 backward. But with DCC, when you're using the 128 speed-step mode, you have 128 speed steps forward and 128 speed steps in reverse. 14 and 28 speed-step modes work the same way.

The first DCC system available (Lenz) had only 14 speed steps. But the NMRA made provisions right from the get-go to have more. Digitrax's first DCC System, the Challenger (now discontinued), would do 14 or 28 speed steps. But with the advent of the Digitrax BigBoy (1994), also now discontinued, all speed steps became available - simultaneously.

All of Digitrax's current systems now provide 14, 28, and 128 speed steps - simultaneously. But don't assume that all systems by other manufacturers also do. Some current systems have implemented 128 speed steps just recently, having only done 14 and 28 speed steps before. Some systems are still limited to 14 or 28 speed steps, not both at the same time.

There have been discussions over the years as to whether 128 speed steps is necessary or not. The nay-sayers would always say, "the real ones don't have 128 speed steps". Well, we're not playing with full-sized locos. We're playing with models. And like everything that gets scaled, all things can't be scaled exactly the same and still appear the same. With model railroad control, the smaller the scale the more speed steps you need to have good control.

Part of the disagreement stemmed from the fact that some people had systems that didn't do 128 speed steps and others did. Being loyal to their system, those with non-128-speed-step systems would argue that 128 speed steps weren't necessary, while those with 128-speed-step systems argued that it's the greatest thing since s_(fill in the blank). It amuses me to hear those who previously argued against 128 speed steps before they had it now tout the benefits of 128 speed steps now that their system does it.

But it goes beyond this personal pride thing.

One day at the Train Mountain Railroad Museum in Chiliquin, Oregon, I discovered why there has been a disagreement on this with some people. Some of the people in the discussion were operating in different scales. I assume the ones that say "Real ones don't have 128 speed steps" don't even operate model trains, or they'd know that 8 speed steps certainly isn't enough for model trains.

Anyway, I was offered the chance to operate a 1/8-scale loco at Train Mountain, so I accepted. This loco ran on batteries, and had a controller on it similar to a real train controller. I don't remember now how many speed steps it had, but I think it was 8. Having only 8 distinct speeds with this scale of loco doesn't provide for a smooth transition from one step to the next. Because the power-to-weight ratio is heavily weighted toward power, the loco would start with a jerk. And you could feel each successive increment in speed, although less and less the faster we went.

So, what's the deal? Real locos have much more weight per horsepower than models. When you give a real loco notch 1, there's so much weight involved that the loco can't jerk to a start like that 1/8-scale loco did. With the 1/8-scale loco, the power is so great for the amount of weight that it could achieve the full speed that notch one could provide in only a second or two. The reason nobody noticed this with N and G scale locos is that we don't ride on them - we can't "feel" it. But with a real loco, the motor has to work to achieve the full speed that the power of notch one will provide. If you understand Momentum, you know what I'm talking about.

Just think about it. When operating a full-size loco, five miles per hour is 7.33 feet (88 inches) per second. Imagine that loco going 88 inches during the first second that it's set to notch 1. A real loco can't do 5 M.P.H. in one second, but our models can. With G scale, 5 M.P.H. is 3.9 inches per second. You can see that you have to have finer control for switching with G scale than you do with a real loco. With HO scale, 5 miles per hour is 1 inch per second and N scale is only 0.55 inch per second. You really have to have finer control for switching at speeds this slow.

So, you see, the smaller the scale you operate, the finer your control needs to be to achieve realistic switching and other operations. While 28 speed steps may be OK for G scale, 128 is certainly a whole lot better for HO and N scales. Of course, if all you want to do is turn your trains on and watch them go, any amount of speed steps is fine.

As far as I know, all systems available today can do 14 and/or 28 speed steps. Some cannot do 128 speed steps. If the system you buy, or have, doesn't support 128 speed steps, your locos can't do 128 speed steps even though your decoders are capable of it.

All of Digitrax's current systems support 14, 28, and 128 speed steps. They come with 128 speed steps as the default. To do 14 or 28 speed steps for any given loco, the system has to be told to do that through a process called Status Editing.

As far as I know, all decoders today are capable of 14 and 28 speed steps. Not all decoders are capable of 128 speed steps. So if you want 128 speed steps, you must insure that the decoders you buy have that feature. All loco decoders carried by Loy's Toys are capable of 128 speed steps.

Having optional decoder speed steps can be intrusive. What's considered optional is dependent upon your system. 128 is the default on Digitrax systems and 14 and 28 speed steps are optional. This means Digitrax's systems will automatically use 128 speed steps. If you purchase a decoder that can only do 14 or 28 speed steps, the address of that decoder must be Status Edited in the command station to do which ever speed step the decoder is programmed to do.