Model Railway Level Crossing Lights
A magnet under the train operates reed switches positioned on the track. The trigger reed switch starts the
sequence by switching on the amber light, a few seconds later the two red lights start to flash. When the
train has passed the level crossing it operates the cancel reed switch which switches off the lights until the
next train arrives. There is a PCB pattern for this project, but you may prefer to build it on stripboard
using the layout provided on this webpage: www.newrailwaymodellers.co.uk/railway_crossing.htm
Parts Required
•
•
•
•
•
•
resistors: 680 ×3, 1k ×3, 33k, 47k, 82k, 270k
capacitors: 0.1µF ×3, 10µF radial ×2
555 timer IC ×3
8-pin DIL socket for IC ×3
miniature magnet(s) - each locomotive needs one
printed circuit board (PCB) - pattern given below
•
•
•
•
•
red LED (3mm best) ×2
amber or yellow LED (3mm)
on/off switch
battery clip
reed switch ×2
PCB component layout
1k
33k
k
ac
555
Bl
Red
270k
Red
r
lou
Trigger
10µF
0.1µF
680
an
0.1µF
o
yc
Red
555
an
680
yc
olo
ur
short -
10µF
1k
82k
Black
short -
555
Blue
Red LEDs
1k
Cancel
0.1µF
Black
47k
short -
Amber LED
Red
680
Track connections
direction of train
TRIGGER
reed switch
•
Amber and
Red lights to
warn traffic
Level
Crossing
CANCEL
reed switch
The reed switches can be held in place between the rails with a small piece of blu tac.
Each locomotive will need a miniature magnet glued to its underside, test first with blu tac,
then use superglue.
THE
ELECTRONICS
CLUB
© John Hewes 2006, The Electronics Club,
www.kpsec.freeuk.com
A kit for this project is available from
RSH Electronics
Circuit diagram
33k
270k
1k
1k
82k
680
1k
0.1µF
8
7
555
timer
6
8
2
3
7
555
timer
4
2
Trigger
1
3
4
680
6
1
0.1µF
amber
red
6
555
timer
2
1
+
10µF
4
9V
3
red
cancel
+
0.1µF
PCB copper track pattern
THE
ELECTRONICS
CLUB
47k
8
© John Hewes 2006, The Electronics Club,
www.kpsec.freeuk.com
A kit for this project is available from
RSH Electronics
10µF
680