Since TMCC was first introduced in the mid 90s, Lionel’s command control locomotives have been limited to 2-Digit addresses; #1 through 99. It was never dreamt of that anyone would ever want or need more addresses than that. But the fans of Lionel trains have proven that false!
First introduced with the 2022 VisionLine Class A, Lionel brings you 4-Digit Addressing capabilities exclusive to the Base3 and Cab3 APP. Since it is not possible to add this capability to existing TMCC/Legacy radios, an all-new protocol has been in development. This continued development is why 4-Digit was limited to special release locomotives until rolling this feature into all Legacy engines in Lionel’s 2024 Volume 2 catalog and beyond.
This new protocol adds a new level of control and interactive experience with Legacy locomotives:
- 4-Digit allows a numeric number to be assigned anywhere from 100 to 9999. Numbers 1 through 99 will continue to use the existing Legacy radio.
- Two-way communications between the Base3 and the 4-Digit locomotive allow for features not seen before:
- Engine identification. When an engine is programmed, it will send its road name, number, and control type to the Base3 which will update the Cab3 APP. No longer will you need to program this information manually or run the engine over a SensorTrack.*
- Automatically import the engine’s image into the Cab3 APP (internet connection required).
*4-Digit engines continue to be SensorTrack equipped and compatible.
Compatible locomotives #
The following table outlines which Lionel locomotives have the 4-Digit addressing capability.
| Locomotive | When Catalogued | 4D Generation |
| VisionLine Class A | 2022 Big Book | 1 |
| Brass Hybrid Early Challenger | 2022 Volume 2 | 1 |
| VisionLine Big Boy | 2023 Big Book | 1 |
| VisionLine TriPlex | 2024 Big Book | 2 |
| Legacy ET44 Tier4 | 2024 April Special Release | 2 |
| All Legacy Locomotives | 2024 Volume 2 and beyond | 2 |
4-Digit Programming #
Programming a 3 or 4-Digit address into an engine is the same procedure as programming a 1 or 2-Digit address with TMCC or Legacy. Remember that 4-Digit addressing is only compatible with the Base3 and the Cab3 APP.
- Slide the PGM/RUN switch on the locomotive to the PGM position.
- Place the locomotive on the track.
- Ensure that the Base3 is connected to the track and powered ON.
- Turn on track power.
- Press ENG on the Cab3 APP.
- Enter the desired unique 3 or 4-Digit address that has not been assigned to another locomotive. It is recommended to use all or part of the locomotive’s road number as an easy way to remember its ID. The example in the image below uses ID 1200, the road number of the Class A engine.
- Press SET on the Cab3 APP. The locomotive’s whistle will sound.
- Slide the PGM/RUN switch back to the RUN position. The 4-Digit ID has now been set.
4-Digit & 2-Digit Addressing #
4-Digit addressing is independent of the traditional 2-Digit TMCC/Legacy addressing. This means that the locomotive can be programmed and operated using both simultaneously.
For example, if the above Class A is programmed with ID #1200, it can also be programmed with ID #12. This would allow the locomotive to be controlled from the Cab3 APP using the 4-Digit address and also be controllable at the same time with a Cab-1L or Cab2 using the 2-Digit address.
The 4-Digit address also includes features that the 2-Digit address does not have. This primarily centers around the 2-way communications. When you program a 4-Digit address, the engine will send its information back to the Cab3 APP such as road name, road number, control type, and more. Programming the same engine with a 2-Digit address will not cause the engine to transmit its info to the APP. This information will still need to be set either manually or by running the locomotive over a SensorTrack that is connected to the Base3.
4-Digit Generations #
You may have noticed in the table above that the last column indicates which “4D generation” is present in 4-Digit locomotives. There are some differences between the first and second generation of 4-Digit technology.
Gen 1 #
This generation uses a separate radio dedicated to 4-Digit addressing. Due to technical constraints with how the radio communicates with the engine’s main processor, real-time metrics like water and fuel are not possible. Instead, these engines are required to cross a SensorTrack to deliver fuel metric data to the Base/Remote.
Gen 2 #
The newest generation of 4-Digit technology incorporates the protocol into the Nordic Bluetooth radio. This has allowed for very fast timing in the system, allowing for the real-time fuel metrics. As your engine runs, you can monitor the fuel and water levels in the Cab3 APP without having to run the engine over a SensorTrack for the data to be updated.
One caveat is that the engine can only operate in either 4-Digit or Bluetooth mode; not both simultaneously. Until now, Bluetooth Legacy locomotives have had a physical Bluetooth ON/OFF switch. Gen 2 engines will have a Bluetooth/4D switch so you can choose the mode you want to run in.
Universal address: In the 2-Digit Legacy/TMCC environment, ID #99 addresses all engines on the track. This is useful to control all engine volume levels, or to stop all engines at once. 4-Digit engines from Gen 1 do not have a universal address outside of 99, but Gen 2 engines do. Use ID #0000 to control all 4-Digit Gen 2 locomotives at once.
Future Development #
This new method of model train control opens up future possibilities for Lionel Trains. The following list describes features not yet incorporated into the 4-Digit engine technology, but will be done by the Lionel Engineering team over the years to come.
- Real-time fuel metrics. Fuel metrics have been part of Legacy engines since track IR & SensorTrack were added. With the 4-Digit bidirectional communications, fuel metrics will be done in real-time without the need for the engine to go over a SensorTrack. Water and fuel levels will constantly adjust in the Cab3 APP.
- 4-Digit Trains. Legacy engines can be built into TR lash-ups #1-99. TMCC engines are limited to #1-9. A goal is to be able to build TR lash-ups with 3 or 4 digit addresses.
