10
Multi-track grade crossings (using photocell detection)
There is an obvious tendency to just add additional photocells to handle additional tracks when you have a multi-track grade
crossing. The problem with this implementation is that the
Grade Crossing Pro/2
cannot differentiate between two trains
traveling in opposite directions on different tracks. As such it could easily get “confused” and not provide the prototypical
sequencing (i.e. the action starts when the train covers a far photocell and the action stops when the train clears the near
photocell on the other side of the crossing). If you will have multiple trains traveling through the crossing area (with outer
boundaries defined by the far photocells) at the same time then you must use one
Grade Crossing Pro/2
for the first track and a
Grade Crossing Pro/2 Expander
for each additional track. See the next section for details on how to connect the
Grade
Crossing Pro/2 Expander(s)
. IF you operate your trains such that only ONE train can possibly go through the crossing area at a
time then you CAN simply add additional photocells (part number PCELL; $2.00 each available from us) for the additional
tracks. In this implementation you will wire the additional photocells in series with their counterparts on adjacent tracks. Figure
16 below illustrates the photocell wiring for a two-track crossing. You MUST go through the photocell sensitivity adjustment
process on pages 5. Do NOT use more than 3 photocells in series for each sensor input (i.e. 3 tracks) as we cannot guarantee
reliable operation!
EN1
EF1
WN1
WF1
EN2
EF2
WN2
WF2
Figure 16 – Two track crossing using extra photocells
Multi-track grade crossings (using between-the-rail infrared detection)
There is an obvious tendency to just add additional sensors to handle additional tracks when you have a multi-track grade
crossing. The problem with this implementation is that the
Grade Crossing Pro/2
cannot differentiate between two trains
traveling in opposite directions on different tracks. As such it could easily get “confused” and not provide the prototypical
sequencing (i.e. the action starts when the train covers a far sensor and the action stops when the train clears the near sensor on
the other side of the crossing). If you will have multiple trains traveling through the crossing area (with outer boundaries defined
by the far sensors), at the same time, then you must use one
Grade Crossing Pro/2
for the first track and a
Grade Crossing
Pro/2 Expander
for each additional track. See the next section for details on how to connect the
Grade Crossing Pro/2
Expander(s)
. IF you operate your trains such that only ONE train can possibly go through the crossing area at a time then you
CAN simply add additional sensor sets (available from us) for the additional tracks. In this implementation you will wire the
additional sensors the same way you did for their counterparts on the first track (i.e. per Figure 10). For example, the blue wire
from ALL of the WN detectors will connect to the WN terminal on the
Grade Crossing Pro/2
.
Multi-track grade crossings (using across-the-rail infrared detection)
There is an obvious tendency to just space out the IR emitters and detectors such that they span all tracks for a multi-track grade
crossing. The problem with this implementation is that the
Grade Crossing Pro/2
cannot differentiate between two trains
traveling in opposite directions on different tracks. As such it could easily get “confused” and not provide the prototypical
sequencing (i.e. the action starts when the train covers a far sensor and the action stops when the train clears the near sensor on
the other side of the crossing). To avoid this situation you will need to use one
Grade Crossing Pro/2
for the first track and a
Grade Crossing Pro/2 Expander
for each additional track. See the next section for details on how to connect the
Grade
Crossing Pro/2 Expander(s)
.
