Page 51 - วิศวกรรมสาร ปีที่ 74 ฉบับที่ 4 ตุลาคม - ธันวาคม 2564
P. 51

Axle Counters                Track Circuits

                                                                               contaminants. Lightly used
                                                                               passenger vehicles on
                                                                               infrequently used lines may
                                                                               also fail to provide an
                                                                               adequate shunt. To avoid
                                                                               safety hazards, track circuits
                                                                               in such problematic areas
                                                                               need closer monitoring, often
                                                                               special technical measures
                                                                               are required as well
                    Type of rail                  Can operate with practically   Rail characteristics
                                                  all widely used rail profiles   (resistance and inductance)
                                                                               should be taken into account
                                                                               in the parametrisation of the
                                                                               TC

                    Installation requirements     After installation training, 5   Drilling of rail required as well
                                                  minutes for each sensor      as installation of insulated rail
                                                  using Frauscher rail claw    joints
                    Bonding                       Not longer required for ACs,   TC bonding is essential to
                                                  leading to less maintenance   ensure that any short circuit
                                                  and greater reliability due to   or disconnection in the track
                                                  the elimination of a weak    circuit is indicated as
                                                  component compared to TCs  apparent presence of a train.
                                                                               Bonding is a weak and
                                                                               maintenance consuming TC
                                                                               component
                    Maintenance requirements     Low – remote calibration and   Frequent and regular
                                                  diagnostics reduce need for   maintenance schedule
                                                  regular maintenance on site   required
                    Track maintenance             Sensors can be easily        Wiring prevents easy removal
                    precautions                   removed, repositioned and    from rail. Can be damaged
                                                  placed back on track         during track maintenance
                    Train passage frequence       Once in two years            Every few days required to
                    required                                                   prevent rusty rails which
                                                                               would decrease electric
                                                                               conductivity between wheel
                                                                               and rail
                    Installation costs            Low                          High
                    Life-cycle maintenance costs   Low                         High


                   All things considered, axle counting solutions convince with several advantages. They play out
                   their strengths also as vital and fail-safe “quick fixes” to existing systems with problematic track
                   circuits.







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                                                                             วิศวกรรมสาร ปีที่ 74 ฉบับที่ 4 ตุลาคม-ธันวาคม 2564
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