Model railroad control point signal control circuit

Trackside signaling at a model railroad control point.

Realistic automatic signal operation for a single or dual track, bi-directional main line.

A control point is a location where tracks merge or intersect, and trackside signals (or wayside signals) govern the safe operation of trains.

The Azatrax TS3 signal control circuit automatically controls three single- or dual-head signals where a single-track main line merges with a branch or passing siding.

The TS5 signal control circuit automatically controls up to five single- or dual-head signals at a control point on a two-track main line.

Train detection is done with simple IR (infrared) sensors placed in or near the track. IR detection requires no resistor wheelsets and no insulating gaps in the rails. The system works equally well in any level of room lighting, even in complete darkness.

The TS5, with four included IR detectors, is able to control signals at several different control point track plans approximating common North American railroad practice. At a control point with five signals, an Azatrax MRD1-NV circuit is also required to provide detection on a branch track.

Find the track plan diagram below that fits the track configuration at your control point.

Click on the track plan to download a full page diagram to use on your layout as a guide to placing the sensors and signals in their proper locations. Print the diagram and use it together with the TS5 installation guide.

The TS3, TS5 and MRD1-NV circuits can be ordered just below the following chart.

To include single-track intermediate signals in your system, see the TS2 circuit [click here].

double track signal bridge, type D heads

Double track signal bridge at the entrance to a control point.

Video introduction to the TS5 signal controller
produced by Model Railroader magazine.

Single track, one turnout	Single track, one turnout requires: One TS3
Double track, no turnouts, four intermediate signals	Dual track intermediate or distant signals requires: One TS5
Single crossover, four signals	Single crossover requires: One TS5
Single crossover with branch, most common	Single crossover with signaled branch requires: One TS5 One MRD1-NV
Single crossover with branch, less common	Single crossover with signaled branch requires: One TS5 One MRD1-NV
Dual crossover	Dual crossover requires: One TS5
Dual crossover with offset branch on the wide side	Dual crossover with signaled branch on the 'wide' side requires: One TS5 One MRD1-NV
Dual crossover with centered branch on the wide side	Dual crossover with signaled branch on the 'wide' side requires: One TS5 One MRD1-NV
Dual crossover with offset branch on the narrow side	Dual crossover with signaled branch on the 'narrow' side requires: One TS5 One MRD1-NV
Dual crossover with centered branch on the narrow side	Dual crossover with signaled branch on the 'narrow' side requires: One TS5 One MRD1-NV
Dual crossover, scissors type	Scissors crossover requires: One TS5
Scissors crossover with branch	Scissors crossover with signaled branch requires: One TS5 One MRD1-NV
End of shared passing siding, dual track main	One end of a shared passing siding requires: One TS5 One MRD1-NV
Diamond crossing, two single tracks	Diamond crossing requires: One TS5-Xing One MRD1-NV if a signaled branch is added

TS3 signal circuit for 1-switch control point.

TS3 installation guide

use at a single switch junction
Includes two IR sensor sets with 2-ft (60cm) wire leads

TS5 signal circuit for a dual-track control point.	TS5 installation guide Includes four IR sensor sets with color-coded wires attached. Choose desired sensor wire lengths:	TS5-Xing installation guide Includes four IR sensor sets with color-coded wires attached. Choose desired sensor wire lengths:
	TS5 and TS5-Xing are expected to be re-stocked by late May. The TS5 and TS5-Xing are actually the same circuit. When you order a TS5-Xing it will ship with the configuration jumpers pre-installed for diamond crossing operation, and a copy of the crossing installation instructions will be included instead of the standard control point instructions.

MRD1 single IR train detector

MRD1 - Single IR train detector
MRD1-NV installation guide

Use with a TS5 control point signal controller when a 5th detector is required.
Single position detector, senses a train at one point on the track.
Includes IR sensors with 2-ft. wire leads.
When activated, the on-board relay contact closes. You connect your circuit to this relay contact, it functions as an on/off switch for your circuit.
Compact size: 1.7 x 1.5 x 0.7 in.
Power required: 8 to 16 volts AC or DC, 40 milliamps.

TS5 signal aspects explained

The signal aspects used by the standard TS5 control circuit are a subset of the Southern Pacific and Union Pacific signal rules. The displayed aspects are similar to what you see on most North American railroads.

This is a "Route Signaling" system. In simple terms, the signal color tells the train crew whether the next block is clear and what to expect at the next signal.

The position of the signal (upper or lower head) tells the crew how turnouts are lined, whether Normal (main route) or Reverse (diverging route). Trains must use a lower speed when taking a diverging route than when taking the main route.

"Speed Signaling" systems have different definitions of these signal aspects, but in most conditions the standard TS5 will display an appropriate aspect for a speed signaling system.

Pennsylvania Railroad and B&O Railraod signaling - We've simplified these aspects somewhat to accommodate the limited types of model signals available, and to make them easier to read. If you desire more prototypically correct aspects, ask us about custom aspects.

Custom Aspects can be set up to more closely match the railroad you are modeling. The chart below shows the ten track conditions the TS5 can recognize and the corresponding standard aspects, depending on the type of signal being used. To order custom aspects, contact us. A one-time $35.00 programming fee applies to the first circuit. Additional circuits with the same aspects can then be ordered at the standard price.

For more in-depth information about North American railroad signal practice, these videos are a good place to start:

Railroading 101, Signaling Systems
by the US Federal Railroad Administration

Reading Canadian Railroad Signals
by Ian Juby

TS5 Signal Aspects

Track Condition

Name

2-head

1-head

B&O

PRR

Main route,
track is clear.

clear

Main route,
next signal is 'approach.'

Advance approach aspects are enabled with a jumper setting on the TS5 circuit.

indicates flashing

advance approach

Main route,
next signal is 'stop.'

approach

Main route,
next signal is diverging clear or diverging advance approach.
Next signal's control circuit must be a TS3 or TS5.

approach medium

Main route,
next signal is diverging approach.
Next signal's control circuit must be a TS3 or TS5.

approach slow

Diverging route,
track is clear.

diverging clear

Diverging route,
next signal is 'approach.'

Advance approach aspects are enabled with a jumper setting on the TS5 circuit.

diverging advance approach

Diverging route,
next signal is 'stop.'

diverging approach

Entering non-signaled territory. Must be able to stop within half the visible distance ahead.

restricting

see note 1 below

Block ahead is occupied or route is blocked by a turnout lined against you.
To maintain proper signal function, do not pass a 'stop' signal.

stop

Note 1 - For a 2-head signal the default restricting aspect is red-over-yellow.
This can be changed to red over flashing red by following the procedure on pg 10 of the TS5 installation guide.

Signals sold separately according to scale:
N scale
HO scale
S scale
O scale

Need signals on a single-track line? The TS2 circuit will connect with your TS3 and TS5 circuits to make a complete modular signal system that is quick and easy to re-configure.
See this page: Single track block signaling