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RocJ Introduction & Setup

ContentMobile ClientsRocJ

Tip: Also try out Rocweb.

The Java based client for Rocrail.
(Support Key needed.)


RocJ is a Java 5+ Rocrail client targeted to MIDs and Pads.
This client is track plan oriented and can be controlled with just a one (left)button mouse or touch screen.
It does not feature an application menu; All actions are context sensitive.

Support Goody

RocJ is a goody for those who have a valid support key installed on the server:

Without a key RocJ will run 5 minutes demo. (152+)

Java Web Start

RocJ can be started directly with Java Web Start:

The first time, or when an update is available, RocJ will be downloaded:


  • Works with all Command Stations supported by Rocrail
  • Touch screen support
  • System monitor
  • Layout:
    • List with all ZLevels
    • Block status color
    • Interactive
    • Fiddle Yard
    • Turntable / Traverser
    • Staging block
    • Module view
    • Zoom
    • SpDrS60 symbols only
  • Block actions:
    • Go with schedule
    • Go to block
    • Dispatch for throttle
  • System actions:
    • Power
    • Auto mode
    • Reset
  • Loco:
    • Throttle
    • Image caching
    • Images in blocks
    • All defined functions


RocJ will use the selected device language if available. It defaults to English.

Add or edit your own language at LaunchPad:
Translations at LaunchPad:


Module View

Level View

Loco selection

The occupied block will not change to red but shows the loco image if available.

Loco functions


Download the latest snapshot of RocJ here:


java -jar rocj.jar

External Accessory Images


Images are searched in the images directory in the working directory of RocJ; The location where RocJ is started.

Filename Format

  • #1 = Accessory number
  • #2 = Orientation:
    1. vertical
    2. horizontal


The image size should be a multiple of 32 in width and height.


Starting with RocJ 122 a scaleable (Fast) Clock panel is added:


  • The clock is synchronized with the server.
  • At divider values above 10 the second hand will not be rendered.


Popup → Options → Clock…


Added in RocJ 133:



  • 12 Functions with LED
  • Tooltips on function buttons (138)
  • Loco selection by image
  • Emergency break

Setup Speak

Add following two lines in the rocj.ini:

speak4block Comma separated list of block ID's
speakcmd Speak command; Can also be a script.

Trouble Shooting

Plan does (partial) not load

Check the plan if it is XML well formed with a tool like "XmlSpy".
Or use the W3C service:
Rocrail and Rocview are using the Rocs parser which is not so strict as the Java one.

rocj-intro-en.txt · Last modified: 2023/08/29 11:17 by rjversluis