Turn- and Transfer Tables

Turntable or transfer table?

A turntable rotates a bridge around a central pivot and is commonly used to reach radial depot tracks or reverse locomotives. A transfer table moves a straight bridge sideways between parallel tracks and is commonly used in workshops and compact storage yards. Both replace a large set of ordinary turnout connections with one movable piece of railway, so only the track aligned with the bridge is physically traversable at any moment.

Any model can be drawn

RailKernel catalogues can contain any manufacturer and model of turntable or transfer table. Their geometry supplies radius, bridge length, number and spacing of positions, connector locations and the dimensions needed for the canvas. You can therefore draw an accurate depot even when RailKernel does not yet know the device’s digital protocol. As with other catalogue items, vendor, catalogue number, image, product page and manual can identify the physical product independently from operational support.

Current operational support

At present RailKernel’s detailed turntable command model is implemented for the Märklin 74862. Its Motorola address range and command functions allow RailKernel to select a destination track, step clockwise or counter-clockwise, preselect direction, rotate, stop or continue the bridge and operate supported sound and lighting functions. Other turntable models and all transfer tables can still be catalogued, placed, connected and displayed, but they do not automatically inherit compatible digital control merely because their geometry looks similar. A generic transfer-table driver and additional turntable command models require explicit implementation.

Place and connect the geometry

Place the table from its catalogue like any other track. Align each surrounding track with the appropriate geometric connector. For a turntable these connectors lie around the pit; for a transfer table they are arranged in opposing parallel rows. A connected connector is automatically considered usable because removing it would break real layout geometry. Unconnected turntable positions can be enabled or disabled manually through Turntable Connections.

Configure exits and track identities

Open the turntable context menu and choose Turntable Connections. Every catalogue connector has a geometric identifier such as T01, while the project can assign the identifier used by the physical installation or decoder. Mark only positions that really exist and can be reached. Clean exit definitions prevent commands to imaginary tracks and make the displayed bridge position meaningful. When track numbering differs between the catalogue drawing and the decoder, this mapping is where those two worlds are reconciled.

Roundhouse sheds

A usable turntable exit can be marked as Shed. RailKernel then draws a radial shed behind that exit, extending it along the connected track geometry where possible. Shed markings describe the depot and make storage roads immediately recognisable; they are not themselves buildings, feedback contacts or automatic parking instructions. Add the surrounding track, blocks, feedbacks and any desired building imagery separately. Automatic “park locomotive in shed” selection is a natural future application of this information, not a current command.

Assign the turntable accessory

A drawable turntable becomes controllable only after a TURNTABLE accessory is associated with that placed track and supplied with the correct command station and base address. The Accessory Monitor treats the supported 74862 as a multi-address device and documents the functions protected by its address range. Without this accessory definition the context menu can still configure geometry, but RailKernel has nowhere to send bridge commands.

Calibrate before operating

Calibration does not move the bridge. It tells RailKernel where the real bridge is already standing. Choose Calibrate Turntable and click the geometric connector toward which the operator-house side of the physical bridge points. RailKernel stores this current connector and can then draw and update the bridge consistently. Recalibrate whenever the displayed position and physical bridge disagree; commanding from a false starting position can select the wrong exit.

Operate the supported turntable

The Operate Turntable context submenu provides one-step clockwise and counter-clockwise movement and the supported 74862 functions for messages, operating sound, beeps, lamps, lantern, Stop and Go. Destination-track commands use the configured connector mapping and base address. Available behaviour still depends on the assigned command station and its driver. Watch the physical bridge during first tests and verify every numbered exit at low risk before relying on it operationally.

Bridge feedback, blocks and trains

A feedback can be attached to the turntable bridge just as feedbacks are attached to track. It can report that a locomotive occupies the moving bridge and can participate in a block definition. Approach and shed tracks need their own feedback and block structure. The bridge is a shared resource: while it is moving or aligned elsewhere, ordinary geometric proximity does not mean that two exits are simultaneously connected. Keep the digital bridge position, real alignment and feedback occupancy synchronized before moving a locomotive.

Use in routes and automatic driving

Treat the table as an operational boundary until the required bridge movement and alignment have been verified. The currently aligned bridge can connect only one pair of directions, and a locomotive must fit completely on the bridge before it rotates or translates. RailKernel does not promise generic automatic depot routing for every catalogue model. Build and test the surrounding blocks first, operate the supported turntable deliberately, and never assume that a visually drawn transfer table has become a digitally protected route element.

If the bridge and drawing disagree

• Confirm that the correct placed track has the TURNTABLE accessory.
• Verify the command station, Motorola base address and protected address range.
• Check that physical exits are enabled and mapped to the correct track numbers.
• Recalibrate by selecting the connector at the operator-house side of the real bridge.
• Verify that connected tracks meet the exact geometric connectors.
• Check bridge and approach feedbacks before moving a locomotive.
• Remember that unsupported turntables and transfer tables are drawings until a matching command driver exists.