Train Actuated Warning Device - TAWD 62/63

TAWD is a audio visual warning device for safe passage at unmanned / manned Level Crossing (LC) and is very essential for the road user and also for train operation . The TAWD has been designed and developed as per European standards (CENELEC) to provide warning to the road users in advance before train reaches the LC Gate.


The application includes:

1. Manned Level Crossing
2. Unmanned Level Crossing
3. LC gates in the yards of cement, steel, petroleum industries etc.

1. Remote Unit
2. Gate Unit
3. Decision Unit
4. Audio Visual Unit and SM's Monitoring Panel
5. SM's Monitoring Panel

Brief Description of Units

Remote Unit: The Remote Units are installed at 2 Km away from the Gate on S/L and D/L sections. The Remote Unit detects the train entry into the Level Crossing section and the same is communicated to the Gate Unit.

Gate Unit: The Gate Units are installed on either side of LC Gate on D/L section. The Gate Units receives train entry information from the Remote Units and vital relay is dropped on 1 st count. When train clears the Gate the stored counts are compared and the vital relay is driven to pickup. The information regarding Drop and Pickup of vital relay is sent to the Decision Unit for actuating the warning.

Decision Unit: The Decision Unit receives vital relay drop information and actuates the Audio Visual Warning. The vital relay pickup command is used to stop the warning. The 1 st train entry and last train out from the LC section is also decided in the Decision Unit on D/L for actuating and to stop the warning. The Decision Unit is also provided with intelligence to actuate warning when train enters towards LC Gate and don't activate the warning when train is going away from LC gate in S/L sections.

Audio Visual Unit: The Audio Visual Units are installed on either side of the LC gate to provide warning to the road users. The Ding-Dong bell is actuated & Red LED lamp glows when train is approaching LC gate. The yellow LED lamp glows and audio is switched OFF when train clears the Gate. This condition continues till next train arrives in the section.

SM's Monitoring Panel: The SM's monitoring panel for TAWD is provided at the control station of LC gate. The information of LC gate & system status is communicated to the panel on ½ Quad cable and indicated by means of LED's. It also provides information regarding fault condition of the system by means of LCD display. The resetting of system is to be carried out by SM from this panel.

Features :

1. Train detected in Remote unit for warning
2. Web type axle detectors.
3. Compatible with 90 R, 52 kg & 60 kg rail profiles.
4. One minute advance warning to road users before arrival of train at gate.
5. Warning stops just after train departs from gate.
6. 10 minute standby mode of operation.
7. Central Power supply scheme (24V) from gate.
8. Data & Power to remote unit is on ½ quad cable.
9. System convertibility to suit S/L and D/L section.

Design:

1. Designed as per CENELEC, SIL- 4 (European standards).
2. 21 K Hz & 23 K Hz high frequency Axle detectors.
3. Micro controller based design with 2 out of 2 decision.
4. Counting through software.
5. Cyclic Redundancy check (CRC).
6. V.21 modem communication (2 wire).
7. Opto Isolated relay drive for Q type 24V, 1000 ohm.
8. Fail safety tests conducted and found OK.
9. MTBF is greater than 20 years.

Specification :

1. RDSO / SPN/179/2003

Development & Field trials:

1. The TAWD has been indigenously designed & developed by CEL. CEL received order for supply of 50 Nos. for extended field trials in Indian Railways. One Double Line system and One single Line system has been inspected and cleared by RDSO .The first system is under installation at gate no. 45 C in Delhi - Rothak section of Northern railway.