Signal Control Products

Overview

The MiniRail Solutions signal system is designed to automatically control signals in response to trains detected on sections of track.

The system is specifically designed to fulfill the demands of automatic signaling required by “Full-Time Bi-Directional” railroads where engineers are able to go “anywhere at any time” (using  turnout motors and multi-headed route signals) as opposed to the less demanding signaling required by uni-directional tracks for train separation only.

While providing train separation, the system also enhances traffic flow by attempting to minimize deadlocks, etc.

Although designed for bi-directional running, the system easily handles uni-directional track where only train separation or multi-entry features are required.  The more advanced features are available as you add more complexity to the railroad (more choice of routes, etc.).

When someone implements automatic signals they will typically use a set of relays to control the signals.  Wires are run from each track segment to relays that control each signal.  Additional wires are run between signals to allow the relays to “know” about the occupancy status of tracks ahead for a signal to display, for example, an “Approach” aspect (it must know the status of the block and the following block).  These relays must be carefully selected and installed to ensure that they will reliably detect trains in any weather conditions which is sometimes not an easy task.

For a dispatcher to be able to see the status of tracks and signals in a relay system additional wires must be run from each track to the dispatch location.  To allow the dispatcher to control switch motors, etc. more wires must be run from the dispatch tower to each individual device in the field.

The MiniRail Solutions signal system is different in that the signals are controlled by small, single chip, microprocessors (“a computer on a chip”) distributed around the railroad.  No programming is required.  The user merely configures the system by setting parameters.

The track voltage is processed by an adaptive conditioning algorithm that removes the effects of weather (wet/dry), wheel noise (leaves, etc.), etc.  I have yet to encounter a track condition that it can not deal with.

Using microprocessors provides a level of flexibility that is not achievable with traditional signal systems.  The system provides the ability to control any signal, switch motor, etc. from multiple points on the railroad (typically, the dispatch tower).  The system can display the real-time status of all tracks, etc. (which tracks are occupied, switch positions, etc.).  These displays can be at any point on the railroad (dispatch, passenger station, etc.).  The system allows adding new tracks, signals, etc. or changing the way the signals operate simply by changing configuration parameters.  No additional wire is needed except that needed to connect your device to the nearest controller.

Because the features of the system are implemented via configuration parameters (downloaded by the user into the controller), system changes or new features are much easier to implement.  No field hardware changes are required except those needed to add or remove physical items such as tracks, signals, switch motors, etc.

The microprocessors are located on small printed circuit cards.  These cards are referred to as Signal Controllers.  The number of controllers required, and their physical location depends on the needs of the railroad.  Locations are selected to minimize the amount of wire needed.

Tracks and signals are connected to the closest controller regardless of the block they are associated with.  This minimizes wire cost as well as exposure to lightning induced voltage surges.

To coordinate traffic through Blocks, Interlocks and Routes, the controllers communicate with each other via a single twisted-pair of wires within a CAT-5/6 cable buried along the right-of-way.  The controllers can also communicate over small data radios.

If so desired, the controllers can be installed in “Stand Alone” mode (no connections between controllers) or in one or more “Clusters” according to the needs of the railroad.

There is no “central computer” involved in controlling the signals.  The control logic is distributed around the railroad within the controllers, thus there is no central PC to fail causing the entire signal system to go out of service.

The system supports one or more PC’s connected to the system to display real-time track status and issue commands to the system (throw turnouts using switch motors, etc.).  (See SComm)

The controllers typically get their power from an additional pair of wires buried with the data cable.  Since the controllers draw very little power, small installations can simply use one or more pairs within the CAT-5/6 data cable to deliver power.

The biggest challenge with solid state signal systems is their vulnerability to nearby lightning strikes.  Careful design of the printed circuit boards along with the on-board protection devices minimizes the possibility of damage to the controllers. (See Living With Lightning)

The controllers detect trains by using “track circuit” technology (i.e.: train is sensed by the fact that it’s axles “shunt” or “short circuit” the rails together).  As an alternative, “Axle Counting” and/or “entry/exit” methods can be added to the system firmware where track circuit detection is impossible or impractical (e.g.: steel rail with welded steel ties) but these alternatives have issues that must be accounted for using additional operating rules, etc. (See Other approaches to automatic signals: ‘Trip Tracks’ and ‘Axle Counting’)

If a controller is unable to communicate with other controllers (another controller is not working, the cable has been cut, etc.) it may not have all the information it needs to properly control the signals in a given block.  In this case, the effected signals will operate in a ‘degraded’ mode.  The controller attempts to display the least restrictive signal aspect while still providing block protection and train separation.  If a controller does not have access to the minimum information needed to provide such protection it will set the affected signals to an “Error” aspect to warn engineers that protection no longer exists and provide a reason code to the signal maintainer.

System Feature Summary

Signal Features

  • Designed from the outset for Full-Time bi-directional, “Go Anywhere at Any Time” running and easily handles uni-directional blocks as a subset of bi-directional control.
  • Blocks are protected from two trains entering simultaneously (cannot be accomplished with simple occupied/unoccupied or ABS/APB systems, see Why ABS/APB Signals Are Not Sufficient).
  • Train Detection automatically adapts to wet/dry conditions, rejects noise caused by dirty wheels/tracks.
  • Block entry points can be assigned a priority.  This allows you to prioritize one or more entry points over other entry points (e.g.: give eastbound traffic priority over westbound traffic, etc.).
  • The system attempts to detect and avoid deadlocks by controlling traffic flow.
  • Traffic can be coordinated across several blocks using “Block Reservations”.
  • Signal aspects are ‘soft’ and can be customized by the user.
  • Signals can be dimmed at night (if you are using the “dimmable” LED driver built into the controller).
  • Signals can be configured as “approach lit” (dark when no train present) as in some prototype practice to save power.
  • Blocks can have an arbitrary number of entry/exit points.
  • Facing-point (route) signals can be configured to display the status of the alternate route in addition to the currently selected route.
  • System can show route status (e.g.: double signal heads at track turnouts) using feedback from motorized turnouts or via micro-switches attached to manual track switches.  The MiniRail Solutions “Switch Point Detector” which detects actual point position can also be used on motorized or manual switches.
  • If desired, you can provide engineers with additional information via “blink/wink” codes in the signal aspects.  For example, the engineer can tell if the signal is at “Stop” aspect due to occupied block, dispatch hold, etc.
  • System can have multiple configurations such as one for Run Days, another for Public Days or Card Order, and yet another for Large Meets.
  • Only 4 wires are required in the right-of-way to support all functionality (typically one CAT-5 cable and a pair of #16 for power).
  • No new right-of-way wires are required to add signals or trackside devices other than that required to connect them to the nearest controller.  If a new controller is needed you just tap into the existing data and power cables.
  • All wires from tracks and trackside devices are “home run” to the nearest controller.  No need for long wire runs to a relay frame.  Easier to layout and maintain and minimizes lightning damage.
  • No relays to corrode, stick or adjust.
  • Functionality can be altered by changing system configuration parameters, no re-wiring or re-programming is required.  There is only one version of the controller firmware to support all functionality.  Controllers only differ in the parameters set for them.
  • Can accommodate wireless connections between controllers in cases where it is difficult to run cable connections.
  • Supports real-time display of track occupancy, etc. on one or more computer monitors with the capability to display on a club web site, etc.
  • Can accommodate preexisting signal heads, semaphores, etc.
  • Drivers are available to control other track-side devices like crossing gates, trigger sound cards, etc.  In general, any device that accepts a digital or analog input.  This includes drivers for electric switch motors and full-size searchlight signals.  If you have a need that is not covered by a current driver I can design and build additional hardware and firmware in a fairly short time-frame.
  • The controller can accept digital or analog inputs from any device, including serial data (axle weigh scale, etc.).  This includes accepting information from switch motors (or micro-switches) to sense which way the points are set.

Dispatch Features

  • System can run in ABS-like (auto) or CTC mode (dispatcher controls switch motors and can place holds on signals).
  • A free PC program provides a real-time track display showing the status of all tracks, switch positions, signal aspects, etc.  It also supports multiple displays, sub-regions (yard, East Subdivision, etc.).
  • All train movements, switch positions, signal aspects, etc. can be displayed at any point on the railroad (typical: Dispatcher position, station track display, laptop for maintenance activities).
  • Any device on the railroad (switch motor, etc.) can be controlled from any point on the railroad (typical: Engineer-operated Route Selection buttons, Dispatcher, Yard Master, etc.).

Diagnostic Features

  • A free PC program provided for monitoring and control.  (Note: the program is NOT required for the signals to operate in automatic mode).
  • Diagnostic program can display track voltages (including strip-chart) in real time.
  • Provides diagnostic information to aid in troubleshooting broken wires, rail joints, etc. including the ability to identify the location of a bad joint/bond wire.
  • Signals blink an error code to aid in locating faults.

The Future

  • Ability to “Replay” track occupancy to determine routing problems, signal violations, etc.
  • Internet display of real-time track occupancy (club website, etc.)
  • Smartphone App to allow use of smartphone as a diagnostic terminal.
  • Smartphone App to allow anyone to see the current track status to decide where they want to go, etc.
  • Voice annunciation of:
    • Trains approaching the yard/station
    • Trains needing clearance by a dispatcher
    • Trains violating a red signal
    • Etc.

After you work with the BC002 controller for a while you will realize that what you really have is a device that accepts analog or digital inputs and sends them to any location on the railroad (possibly combining it with other inputs) to activate a digital or analog device at a remote location, all without adding extra wire.  I’ll bet you can think of many uses beyond signals such as axle-load scales at the yard or station exit to stop trains that are over weight, wheel “back-to-back” sensors to detect wheel sets not in gauge, etc.

At a track in Florida the signal power is controlled by a re-settable timer that runs for about six hours after the last press of the “On” button.  Sometimes during meets the signal power goes off because people forget to push the button periodically.  A solution being installed is to have the controller in the tower (the same controller that provides the dispatcher display connection) turn off the signal power 60 minutes (default) after the last train movement.  To do this the controller simply monitors for train movements and activates a relay that releases the latched power relay when movements are no longer taking place.

If desired, a user can use other third-party software to monitor and control the system.  One alternative is the JMRI system used by the “table top” railroad model community.  The software could be interfaced using either a controller containing firmware designed for the purpose (see me for details) or you could use the Windows DLL available from me that will process the system CAN bus messages into a set of “Observable Objects” that your software can use.  An example program is shipped with the DLL as part of SComm.

The above program could be used for operator monitoring and control (similar to SComm) or you could just configure the field controllers to detect tracks and drive signal heads.  Your PC software (JRMI, etc.) could provide all block/interlock functionality.  Warning: Doing this would create a single-point-of-failure – if the central PC is down or can’t connect to the network, all signals will be inoperative.

For more information see the Documentation page.

Feel free to Contact Me with questions or for more info.

All of the surface mount components are placed using my Quad IVc pick-and-place machine (see: Videos page).

Available Signal Control Components

System Controller (Part # BC002)

This is the heart of the system.  All controllers run the same firmware and are distinguished only by the setting of their operating parameters.  You configure the system by setting parameters, there is no programming required – similar to using a PLC (“Programmable Logic Controller”) specifically designed for railroad signals.

Multiple controllers communicate over the data bus to control the signals.

Each controller can sample 8 tracks (or other inputs) and directly drive 16 signal head lamps (or other outputs).  Multiple expansion modules can be added to the controller for IO expansion and special purposes such as activating switch motors, full-size searchlight signals, crossing gates, etc.

Controller Base Card (part # BC002-02)

The controller card plugs into the 40-pin connector on the Base Card.

This card contains the lightning/surge protection for the 8 track inputs, the 16 signal head outputs and the Data Bus.  It also provides convenient screw terminals for all field wiring.

Cable Interface Card (Part # BC020)

The Cable Interface Card provides a convenient termination for the power and data at each controller location.

It includes a convenient power switch, power indicator, and a regulator that allows using power bus voltages up to 30 volts.  This 12v regulator allows for long power runs without additional transformers or access to AC supplies and can supply other devices such as switch motors, etc.

The card provides additional lightning/surge protection as well as jumpers that can be used to isolate power and data bus segments to isolate cable faults.

A single Cable Interface Card can be used to connect multiple controllers in a given equipment cabinet.  I also recommend one of these be used to connect a power supply to the power bus.  This will help protect against surges coming in from the commercial power grid.

Low Side Driver (Part # BC009)

This is an extension card that adds 8 general purpose output channels to the BC002 controller.

The outputs are “Low Side” meaning that, when active, they connect the output terminal to ground.  One side of the load is connected to the output terminal, the other side of the load can be connected to any positive supply up to 15 volts.  Maximum current is 500ma per channel.

Each output has an associated LED indicator and surge protection device.  Each output channel also has an associated “fly-back” diode so it can directly drive relays, solenoids and other inductive loads.  It can also be used to provide additional signal head outputs where the cable run is long, requiring additional lightning protection.

Serial Isolator (Part # BC011)

The Serial Isolator is used with the FTDI USB-To-Serial cable (available from me or other suppliers) to connect to the controller’s diagnostic port.

The cable and isolator are used to connect a PC/laptop to a controller for diagnostics, load new firmware or configuration, setup a dispatcher terminal, etc.

The Serial Isolator provides complete isolation between the PC/laptop and the controller.  This eliminates any chance of ground potentials, etc. from damaging the controller’s diagnostic port.

TWI Opto Driver (Part # BC015)

This is an extension card that adds 8 optically-isolated general purpose output channels to the BC002 controller.

Each channel has a + and – terminal to connect to the load.  The load is fully isolated from the controller up to 5,000 volts.  The output is limited to 15 volts at a maximum current of 50 ma.  Each output has an associated LED indicator and surge protection device.

This expansion card can also be used to provide additional signal head outputs where the cable run is long, requiring additional lightning protection.

Base Board Opto Adapter (Part # BC016)

This board is designed to provide additional lightning and surge protection to the 16 signal outputs built into the BC002 controller.

The load is fully isolated from the controller up to 5,000 volts.  The output is limited to 15 volts at a maximum current of 50 ma.  Each output has an associated LED indicator and surge protection device.

If you are in a very lightning prone area (such as Florida) and/or you want to connect signal heads that are a significant distance from the controller I recommend using this adapter.  This adapter can also be used to isolate other TTL active-low signals you might have developed yourself.

Relay Board (Part # BC017)

This is an extension card that adds three relay outputs.

In “Normal” mode the relays provide an always-on, “reversing” output to the K1, K2 and K3 terminals.  They are designed to operate turnout motors that move the points to one direction with “forward” polarity and the other direction with “reverse” polarity.

In the “Linked” mode the load is connected to K2 and K1 provides an On/Off to K2 (K3 is always in “Normal” mode).  This is specifically designed for driving full-size searchlight signal heads (or scale signals) that use a magnetic “Slug” motor.  These display Green for forward current, Yellow for reverse current, and Red for no current.

There are jumpers on the card to set Normal or Linked mode, relay output power source (on-board or external), and the card’s address.

A BC002-18 Relay Expansion Card can be added to this card via a ribbon cable (provided with the BC002-18) enabling it to drive an additional 5 “Normal” outputs or 2 additional “Linked” outputs and one “Normal” output.

Relay Expander (Part # BC018)

This card connects to a BC017 Relay Board via the supplied ribbon cable.  This board adds an additional 5 relays without taking up an additional expansion bus address.

Relay pairs K1/K2 and K3/K4 can operate in Normal or Linked mode (see BC002-17 Relay Board above for more information).  A 6″ long ribbon cable jumper is included to connect this board to the BC002-17 Relay Board.

Switchpoint Detector Interface (Part # BC026)

Two BC027 Switchpoint Sensors are connected to this module.  This module supplies a single multi-level analog output used by the BC002 Controller to detect the position of the switch points.  In addition, the module contains two DPDT relays, one for each switch position.  These relays can be used to drive a switch dwarf signal directly in response to point position and/or used to drive a traditional relay-based signal system.

Switchpoint Detector (Part # BC027)

This Switchpoint Sensor will reliably detect the actual position of a turnout switchpoint.  Unlike standard methods using microswitches in a turnout motor or on switch mechanisms, this detector senses the actual location of a point and will not indicate the point is closed unless it is actually closed.  No more derailments caused by clearing trains through a turnout that has a rock in the point.

Switchpoint Detector Interface (Part # BC0028)

This is functionally equivalent to the BC026 Detector Interface except that it does not have the two relays needed to drive traditional signal systems or dwarf signals directly.  It is designed to work specifically with the BC002 Signal Controller.

Profile Insulators (Part # A0001)

These insulators are intended to be placed between the ends of rails that are to be insulated from each other.

They are CNC cut in “West Coast Rail” profile from 1/8″ thick plastic.

(other profiles available on request).

I will also be making available injection-molded “joint bars” as soon as I get time to make the mold.