Connect to WiThrottle Server
Enter the JMRI computer address and the port shown by WiThrottle Server, commonly 12090.
LocoLink client for JMRI WiThrottle Server
A JMRI WiThrottle app.
LocoLink beside your railroad.
LocoLink can connect as a WiThrottle client to a running JMRI WiThrottle Server on the same local network. Use LocoLink on Windows, Mac, iPhone or iPad for track power, locomotive speed and direction, decoder functions and turnout commands while JMRI remains the hardware bridge.
JMRI WiThrottle clientLocal TCP connectionWindows + Apple
JMRI remains the bridgeLocoLink is the operator app; JMRI connects the WiThrottle Server to the configured railroad hardware.
Port 12090Common JMRI default
Local networkRecommended route
No AndroidNot available
30 daysPro trial
Verified client scope
Use the JMRI bridge without hiding what each component does
The WiThrottle route is deliberately described as a client/server connection. Feature availability still depends on the current LocoLink platform, JMRI version, WiThrottle preferences and connected command station.
Control track power
Read and change the power state through the WiThrottle connection before operating a locomotive.
Drive locomotives
Acquire an address, set speed and direction, and keep emergency stop immediately available.
Use decoder functions
Operate available function numbers through the active JMRI throttle connection.
Operate turnouts
Send turnout commands through JMRI using its published WiThrottle panel messages.
Keep the LocoLink project
Use LocoLink’s roster, throttles and visual track plan around the same operating workflow.
Local setup
Connect LocoLink to JMRI in three controlled steps
Keep the JMRI computer awake, use the local network and test one low-speed address before relying on the complete layout.
Start JMRI WiThrottle Server
Open the WiThrottle Server window in JMRI and note the local IP address and port it displays. Confirm that JMRI already controls the command station.
Select JMRI / WiThrottle in LocoLink
Use the shown JMRI computer address and port. Apple devices need Local Network permission; a firewall must allow the JMRI connection.
Prove one safe command path
With one locomotive on a clear section, test track power, emergency stop, address, low speed, direction and one known function before adding turnouts or a full track plan.
Connection boundary
What LocoLink and JMRI each do
This route uses JMRI’s published WiThrottle protocol. It is different from LocoLink’s direct native connections to systems such as Z21 or DCC-EX.
| Part | Responsibility | Important limitation |
|---|---|---|
| LocoLink | Operator interface for track power, locomotives, functions, turnouts and the LocoLink project | Android and Linux editions are not currently available |
| JMRI WiThrottle Server | Accepts the local client connection and translates supported WiThrottle actions into JMRI controls | JMRI must remain running and the WiThrottle Server must be enabled |
| JMRI hardware connection | Connects JMRI to the configured command station and railroad interfaces | Hardware support and exact behaviour are determined by JMRI and the selected system |
| Local network | Carries the TCP connection between LocoLink and the JMRI computer | Guest isolation, firewalls, sleep mode or a wrong subnet can break the route |
| Roster and panel data | JMRI may publish roster, function-label, turnout and route information to compatible clients | The visible subset can differ by LocoLink platform and JMRI configuration |
| Decoder programming | Use the documented programming workflow for the connected command station | Do not assume every DecoderPro operation is exposed through WiThrottle |
Compatibility reviewed . JMRI publishes the authoritative WiThrottle protocol and server and client guide. LocoLink is independent software and is not an official JMRI product.
JMRI connection explained
A local client route, not a replacement for JMRI
LocoLink is independently developed by Westerman. It is not produced, certified or endorsed by the JMRI project. JMRI names the open-source server and hardware bridge; the app on this page is called LocoLink.
Start JMRI and confirm that its own throttle can control the exact command station. Then open WiThrottle Server. LocoLink connects to the local TCP address and port shown in that window. The common default port is 12090, but the value displayed by JMRI is the one to use.
Keep the JMRI computer awake. If it sleeps, closes the server or becomes unreachable through the firewall, the client connection is lost. Use the heartbeat and emergency-stop behaviour as safety tools, not as a substitute for commissioning the layout at low speed.
Direct connections remain separate
LocoLink also has direct adapters for selected command stations. Choosing JMRI / WiThrottle means JMRI intentionally remains between LocoLink and the railroad hardware. That route can be useful when JMRI already owns the interface, roster or established layout configuration.
Do not expose the WiThrottle port directly to the public internet. Keep normal operation on the trusted local railway network. For remote access, use a properly secured network design and JMRI’s current guidance rather than simple public port forwarding.
See the wider model train control software guide, compare the best model train app for each workflow, or use the direct DCC-EX throttle route when JMRI is intentionally not part of that setup.
FAQ
Frequently asked questions
Does LocoLink work as a JMRI WiThrottle client?
Yes. Select the JMRI / WiThrottle connection in LocoLink and use the local address and port shown by JMRI WiThrottle Server.
Which LocoLink platforms can connect to JMRI?
LocoLink is available for Windows, Mac, iPhone and iPad. Android and Linux editions are not currently available.
Does JMRI need to stay running?
Yes. In this connection route, JMRI remains the server and hardware bridge, so its computer and WiThrottle Server must stay active.
What can LocoLink control through WiThrottle?
The verified common scope includes track power, locomotive speed and direction, emergency stop, decoder functions and turnout commands. Additional roster or panel data can vary by platform and JMRI configuration.
Does LocoLink replace DecoderPro?
No. LocoLink has its own decoder tools, but JMRI DecoderPro remains a separate programming environment and not every programming action is exposed through WiThrottle.
Is LocoLink an official JMRI app?
No. LocoLink is independent software that implements JMRI’s published WiThrottle client protocol.
Can I use JMRI WiThrottle over the public internet?
Normal LocoLink operation should remain on a trusted local network. Do not expose the WiThrottle port directly to the public internet.
Is LocoLink free to try with JMRI?
LocoLink is free to download and includes a 30-day Pro trial with no payment today. Continued Pro use is paid.
Verification
Official JMRI protocol sources and LocoLink product evidence
JMRI documentation defines the server, protocol and network responsibilities. LocoLink documents its current platforms and client scope; no JMRI endorsement is claimed.