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Summary: A throttle (or Cab) is a way to control the locomotives and other aspects of the layout (turnouts, animation, lighted passenger cars, etc).


A Throttle (or "Cab" if referring the analog term) is a method to control the locomotives and other aspects of the layout (turnouts, animation, lighted passenger cars, etc).

There are many types of throttles available, with some features overlapping various types. The variety of throttle types ranges from stationary, tethered (throttle connected via wires), memory walk-around, and tetherless - no wires - using infrared and radio. Each of these can be anything from full-featured to simple basic throttles, but not necessarily with all the other options. Lets break this down.


Let's use the MRC Command 2000 type command station for this example. This is a stationary unit with three throttles. If you're going to have others run trains with you, everyone will have to crowd around the base unit. Throttle 1 controls an analog (no decoder) locomotive, throttles 2 & 3 control DCC equipped locomotives. It should be noted that with this system, you can add one walk-around throttle. MRC's Command 2000 walk-arounds have two throttles (4 and 5) ; however because of the architecture, throttles on walk-arounds control only addresses 7 & 9 or 8 & 10. This system supports up to 10 addresses with the wireless throttle, or six with the base station alone.

Others, such as CVP Products EasyDCC includes two throttles on the command station with the ability to add plug-in jacks around for additional walk-around throttles.

The Digitrax Zephyr has one throttle. Expansion is possible via LocoNet, to a limit of 20 throttles. Further expansion is possible by converting it to a booster and using it in conjunction with another command station. It also features a Jump Port which allows a powered analog throttle, such as a power pack, to be connected to the command station and control a DCC equipped locomotive.


NCE Power Cab, tethered throttle

A tethered throttle is like the Digitrax Big Boy starter set with the DT200 throttle and DB100A booster. It is on a seven-foot cord and must remain plugged in while trains are running. The DT200 functions as the command station, so disconnecting it shuts down the system.

Most manufacturers won't tell you a throttle must stay plugged in. If they don't say "all walk-around", or something to that effect, you can expect at least one throttle to not be walk-around.

The NCE Power Cab is another example. Since the command station and booster are integrated into the handheld throttle, disconnecting it results in everything stopping. By adding a command station such as the Smart Booster, the throttle can be used like a memory throttle.

Memory Walk-Around

CVP Throttle for walk around operation

A memory walk-around must be plugged in to actually control the trains. However, you can unplug it to move the throttle to another location and plug it back in. During the time the throttle is unplugged, the train continues to run at the same speed and direction it was running when the throttle was unplugged. Be sure to check your system specifications before buying a DCC system if you want all your throttles to be "memory" walk-around.

  • All Digitrax systems support this except for the Zephyr throttle (Built into the command station/booster) and the Big Boy.
  • Digitrax's infrared throttles can also be used as a memory walk-around if you take them to a friend's layout that doesn't have an infrared system. Digitrax's radio throttles are both infrared and memory walk-around, they are the most versatile and will operate under any circumstance.
  • EasyDCC wired throttles have memory and the trains will continue while the operator moves to another location to plug in. The throttle bus is durable and flexible coaxial cable.


Tetherless, or wireless throttles communicate either by radio or infrared light. Each of these has two communication modes: simplex and duplex. Simplex has one-way radio control. This means that there is only communication from the throttle to the DCC system. The throttle cannot receive any information from the DCC system, or command station. The throttle must be connected to the layout by its cable when selecting a locomotive since this action requires two way communication.

An example of why you need duplex communication to acquire a locomotive: Let's say the yard hostler has put a train together and leaves the loco running at 5% throttle for you to acquire and take out. The only way your throttle will know the locomotive is already running forward at 5% throttle is if it can get that information from the command station at the time you select it. This process requires two way communication. Once selected, only one way communication is required for you to control it.

NCE Wireless Throttle

Duplex (bi-directional) radio allows you to perform these functions without having to connect your throttle to the layout.

  • Digitrax offers infrared and radio throttles that are simplex - that is they must be plugged into to acquire a new locomotive. Digitrax also offers duplex throttles that do not have to be plugged in to the Loconet to select a loco. Although compatible with the infrared receivers, they require a different receiver from the simplex radio throttles for radio operation.
  • EasyDCC radio throttles are simplex radio transmission and communicate to wireless receivers located near the layout. Up to 16 wireless throttles may be active on a EasyDCC system and users can select locos wirelessly.
  • NCE radio throttles are simplex and duplex. The Pro Cabs (ID 2-17) are duplex while engineer cabs (CAB04/CAB05) (ID 19-47) are simplex in that information is not transmitted back to the throttle to update the LCD display (these throttles don't have the displays). Users are able to select locos wirelessly.
  • Digitrax has discontinued the Simplex throttles. Some of the parts are no longer available, so Digtrax will not make new simplex throttles and will use their existing parts inventory for repairs.
  • Please list other wireless systems here that are simplex/duplex and if they are infrared and/or radio.

An infrared (IR) throttle works almost like a simplex radio throttle - the main difference being reception. Because it uses light signals, it will not have the range of the radio throttle. You cannot use an infrared throttle outdoors as their IR signals cannot compete with the sun. Depending on the layout of the room, your system may require more receivers in rooms that are not conducive to bouncing light signals around.

Tetherless (Wireless) Systems

Functions Supported
Number of Throttles Supported
Frequency Band
Range in Metres
More than 20
2.4 GHz
900 MHZ
More than 32
90 MHz
Notes: All systems can support Functions 0 to 29, depending on the throttle used.

All systems support the use of multiple receivers/transceivers.

All support using individual identification codes so multiple systems can be in use without interference (in theory) between them, at for example, a train show.

Multiple throttle types can be used (they must be the same brand).

ESU Mobile Control II

ESU has launched a small, handheld wireless WiFi throttle based on an ARM processor running Android. It can interface with their command station using WLAN (Wireless LAN) or USB protocols.

Currently it is only supported by ESU Command stations but ESU is willing to work with other systems. It will supercede the ECoSControlRadio.


Computers can also act as throttles, controlling trains around your layout so that you can spend your time doing other things. Please see connecting your computer to DCC for more details.

WiFi Throttle

Mobile devices on a WiFi network running a throttle app can act as full function throttles. Some systems require an intermediate personal computer running server software whereas others do not. See WiFi Throttle.


Some throttles have the capability of controlling more than one train at a time. Some throttles have more than one knob, or another method, which allows easy control more than one train at a time.

Some throttles have displays, others don't. However, those that don't usually have a way to tell what's going on with the train. With some throttles, there are wheels atop the throttle which lets you know which train you're controlling. You can tell the speed by simply looking at the knob.

Some throttles have one or more knobs for train control, some have buttons for train control, and some have knob(s) and buttons for train control.

Connecting Throttles

Throttles are connected with the command station via a throttle network. Please see the Throttle Network article for more information.


We need some people with experience on the systems to write these hints, especially the non-Digitrax stuff!

Here are links to each manufactuers "hints" page.

See Also

External Links

ESU Mobile Control II