Page 50 - วิศวกรรมสาร ปีที่ 74 ฉบับที่ 4 ตุลาคม - ธันวาคม 2564

Axle Counters (AC) are based on a completely different technology and don’t have to rely on the
electrical properties of a track section. And there are many more differences between TC and AC
in installation and operation. The decisive advantages of Axle Counters include, for example: Cost
efficiency in installation and operation, lower maintenance requirements, possibility to provide
additional information and flexibility.

The following table compares the features and characteristics of both technologies directly:

Axle Counters Track Circuits

Functional Scope Track vacancy detection, Track vacancy detection, rail
direction, speed, number of breaks, cab signalling
axles
Compatible with electric Yes Special measures required
tracion depending on traction and rail
type
Track section length Theoretically unlimited, Two miles maximum. Long
depending on network block sections can be
structure. One single AC equipped with multi- section
system can replace many track circuits, which is a
track circuits, giving improved costly solution
reliability and cost
effectiveness
Rail breakdown detection No Some breaks, if clean
Reset required after error Yes – remote and local reset Not required
options available
Can monitor complex Yes, without restriction Yes, with complex designs
switches and crossovers required
Maximum speed 280 mph (450 km/h) 155 mp (250 km/h)
Sensitive to environmental Virtually immune to these Can be significantly impacted
conditions (heat, snow, conditions, (potentially by any of these conditions
water, road salt, rust debris, affected by metallic debris)
etc.)
Ballast resistance independent of ballast TCs cannot operate on track
conditions and therefore ideal with steel sleepers, metal
for use in long wet tunnels bridges, wet tunnels, etc.,
and in locations where ballast where the running rails are
may become saturated by not isolated from each other
(salty) water or where the minimum
allowed ballast resistance
cannot be guaranteed

Wheel shunt resistance Not affected by the value of Loss of track circuit shunting
the train shunt. ACs provide capacity is a serious hazard
highly reliable train detection and may lead to wrong-side
on infrequently used lines failures. Electrical wheel-to-
and in the presence of rail contact may be
intensive leaf fall permanently compromised by
excessive sanding, dust,
fallen leaves or

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วิศวกรรมสาร ปีที่ 74 ฉบับที่ 4 ตุลาคม-ธันวาคม 2564