With out a means of detecting a train on the track or while in a block then your signals will be just pretty looking signal
heads along the track. Their are two ways of detecting a train on the rail. We at Grand Scale Signal Company use a
metal proximity sensor and the prototype standard gage railroads use shunted rail (if you really want shunted rail we can
build our controllers for a shunted rail system). Below is a list of Pros and Cons of each type of detection system:
For comparison, both signal blocks are 900 feet long with rail joints every 30 feet.
Shunted Rail
1. All rail joints must be bonded together by means of a
bonding strap usually a heavy gage wire welded on
outside of the railhead on either side of the joint. Cost of
Wire, Welder and Labor time at $35.00 per joint times 60
joints equals $2,100.00 or more.
2. To divide two signal blocks from each other they
must be insulated at two rail joints, one joint on either
rail. The joint bar must be insulated from the rail, an
insulating sleeve around each joint bar bolt and an
insulating disk the shape of the railhead to keep the
railheads from coming together. The cost of materials
and labor time would be about $200.00 per joint times two
joints equals $400.00
3. Turnouts (switches), any turnout located in or at a
signal block must be insulated. The throw rod insulated
from the points, the bar between the points must be
insulated, the frog insulated in all four directions and any
other metal spacers and/or guide rails as well. The
typical cost would be between $750.00 to $1,500.00 per
switch.
4. Gage Bars must be insulated for a shunted rail
system to work at a cost of about $100.00 per gage bar.
5. Additionally if your using metal ties, at least one rail
would be required to be insulated from the ties. Should
the tie spacing be every 18 inches, you would have 600
ties to insulate. The cost of materials and labor time
would be about $200.00 per tie times 600 ties equals
$120,000.00.
6. Rusted rail on a railroad which is used once a week
and even one or two times a month would require
running a six car train with an engine through a signal
block five to fifteen times before the railheads would get
to be clean and shinny along with the wheels on the cars
and engine before the signal system will start to function
reliably.
7. Rail on wood ties soaked in water and/or water on or
over the rail will shunt out a shunted rail system and the
signal system will be then be faulted (signal blocks will be
red and a grade crossing will either be constantly
operating or will operate once and then shut down).
Until the water resides and the ties dry out, then the
signal system would be able to recover and then operate
normally. Even if your rail were on plastic ties, any kind
of water on or over the rail would put the signal system
in fault.
8. Should an Engine, a Car, Speeder, MOW Equipment
be placed on or removed from the rail in any signal block
it would be detected and the signal system would either
go to a Red Block or to a Clear Block.
9. On a shunted rail system a broken rail would be
detected and the signal system would go to a red block.
The Power Supply for a shunted rail is located in the
middle of the signal block. If their is a broken joint bar,
it would not be detected due to the bonding wires across
the joints.
Sensor Rail
1. No rail joint needs to be bonded together. Cost of
materials and labor to do nothing at each joint is $0.00
times 60 joints equals $0.00.
2. No need to insulate any rail from each other between
two signal blocks thus no costs involved. Also no need to
divide the signal block at a joint, may be done in the
middle of a rail. However, you would need to install the
three sensors that comes with each of your two
controllers at a cost of $20.00 labor for each sensor for a
total cost of $120.00.
3. Turnouts (switches), No need for any kind of
insulation. However you would need to install the four
sensors that are already included in the controller we sell
to you. The only extra cost would be the labor to install
the sensors. Around $80.00.
4. No need to insulate any gage bar in a sensor rail
system thus no cost to you.
5. And if your using metal ties then as above no need to
insulate either rail from the ties.
6. On a sensor system it does not matter how much rust
is on the railheads or car and Locomotive wheels. A
sensor system will work the first time and at all times!
7. Rail on wood, plastic or even metal ties standing in
water will not be affected by the water. The sensor only
detects the passing of a metal wheel. Water, rock, dirt,
wood, fingers, animal feet and anything else that is not
metal will not be detected by a sensor.
8. Should an Engine, a Car, Speeder, MOW Equipment
be placed on or removed from the rail in any signal block
it WOULD NOT BE DETECTED and the signal system
will not go into a Red Block or Clear Block. Although a
person would be able to go to signal location and take a
metal object and run it over the Clear Sensor to clear the
block once the item is removed from the rail. Like wise,
that person could also trip the block sensor and provide
protection when placing an object on the rail.
9. On a sensor system neither a broken rail or a broken
joint bar would be detected. Although, I have seen only
one broken joint bar at the WF&P RR that had been in
the track for over 55 years. NO Grand Scale railroad has
had a broken rail at anytime!
Model Number: TBD-1TSE Single Track Controller - Start/End of Signals $ 995.00
Controller includes a dual power supply, two back-up batteries, two track sensors with rail mounts, On - Off
signal light power switch located on the bottom side of the controller box. The enclosure is an all metal weather
tight box with a hinged door which is held closed by two screws and an optional pad lock (you supply the lock).
By a toggle switch also located on the bottom of the box you may select the signal light(s) to operate in Always
On mode or Approach Lit mode (signal lights will come only if train is occupying the signal block and will go out
when the signal block is clear of all trains). Additionally, if you run wiring to a central point (EI: a dispatchers office,
communications or operating center), then the controller my be set-up to operate in either DTC or CTC modes.
Model Number: TBD-1T2B Single Track Controller - Two, One Half Blocks Signals $ 2,195.00
Controller comes with all as listed above except it has three track sensors with rail mounts.
Model Number: TBD-1TSDS Signalized Turnout Controller with Dark Siding $ 2,995.00
Controller comes with all as listed above with the following exceptions and additions: Four track sensors with rail
mounts, switch point position detection switch box, interlocking control logic which will display a STOP indication
in all directions while the switch points are in between the straight or diverging routes. Once the points are lock-down
in the straight or diverging route then whichever direction is blocked will have a STOP indication.
Model Number: TBD-1TSLS Signalized Turnout Controller with Siding Detection $ 3,495.00
As in the description of the above TBS-1TSDS but with full siding detection.
Model Number: TBD-2TCOC Two Track Crossover Controller $ 5,995.00
Comes with eight track sensors and rail mounts, two switch point position detection switch boxes, four power
supplies, full inter-locking and a larger box to house all the components in.
Model Number: TBD-1T1TDIA One Track by One Track Diamond Crossing $ 8,995.00
Very large enclosure box with four power supplies & batteries, 12 track detectors with rail mounts, full inter-lock
giving priority to whichever direction is detected first to give clear passage over diamond crossing. (Please Note:
if this unit is to be used for just the diamond crossing the you will need to add 4 - TBD1TSE controllers to conplete
the set)