- Contact Us
- CBTC
- Network Operations
- On Board Computer
- Wayside Equipment
- Home
Advanced Digital Wheel Sensor (WCU)
On-board 9.5" Mini-Rack with 6 Modules; WCU, CMU, LCU, TSU, VIOS & CBTC System Card.
Wireless, Solar Powered Evaluation Unit (EVU)
The wayside interface unit is a modular wayside system which interfaces to all existing track equipment and provides wireless or wired communications with other SafeNet CBTC system modules. With the proper selection of modules, virtually any WIU requirements, including communications, train detection, train weighing, PTC or collision avoidance and switch /signal interlocking can be accomplished.
These low power modules can operate by solar power and may communicate with a variety of radio communications equipment and protocols. The modules available include:
The vital WCU is the fundamental unit of the WIU used for train location determination and track occupancy and track discrimination purposes. The WCU measure train speed, direction, train length, wheel (axle count) from 0 to 200 mph with better than 0.1% accuracy. The vital WCU is used to build a check-in check-out system where wheel are counted into a block and upon exit of a block. When the block has a positive wheel count, it is marked as occupied. Our patented quadrature detection technology reduces wheel count errors to virtually zero.
Virtual blocks are created end to end which provide occupancy data as well as speed and a calculated progression into a block. This is a vital detection method which does not require any electronics on-board a train or car. It is used as a primary train location system that is safe. It is enhanced by available GPS, dead reckoning and in-cab signaling.
The WCU can drive a VIOS board to provide signals at the endpoints of each block. A block can be as short as 6 feet or more than 2 miles. It is limited only by communications limits. The WCU does not interfere with any existing track circuits and does not require insulated joints or a good ballast. It is also ideal for use in damp subway or tunnels and installations with steel ties.
Logic Control Unit (LCU)
The LCU board provides the diverse logic control processors. This dual system use n-version programming to provide diverse calculations and control requests where both are written and implemented differently but must provide the same output decisions.
The LCU interfaces with the Vital I/O System to provide vital inputs and outputs to field equipment, such as signals, track switches, hotbox detectors etc.
Communications Management Unit (CMU)
The communications module supports multiple communications protocols and operates three radio systems simultaneously, as well as wired RS485 isolated twisted pair and RS232 interfaces to other equipment. The CMU has RS232, RS485, FHSS radio communications and Internet TCP/IP connectivity. Protocol conversion capability supports interconnectivity with other radio systems.
TrackScale Unit (TSU)
The load cell interface module allows train weight to be measured for each wheel set and records and calculates total train weight and train length. This allows this information to be broadcast to the train for assisting in determination of its breaking distance algorithms.
Vital In/Out System (VIOS)
This module provides vital inputs and outputs utilizing bipolar inputs and outputs at 12V for interfacing to all existing track logic and control and signals. Command requests from the EVU must be in two diverse forms and will only operate when both agree.
The EVU modules are the base stations that are deployed on small towers trackside. The EVU communicates with the Network Operation Center (NOC) to update its databases and movement authorities. Once loaded, the EVU will operate from its database even if NOC is down for a period.
The EVU holds the database of all track specific data and speed restrictions. This includes routes, route segments, blocks, and monitors which blocks and segments are busy. The EVU communicates with the central operation centre which provides specific movement authorities for mobile equipment. The EVU has RS232, RS485, FHSS radio communications and Internet TCP/IP connectivity. A web server is included which hosts up to 40 pages of dynamic data pages as well as encryption and data security features.
In a PTC installation, the EVU’s reside about every 2 to 5 miles and serve as base station to control intermediate Wayside Interface Unit’s (WIU’s) and as gateways to communicate with NOC and trains.
The EVU's host the SafeNet CBTC operation software which considers the NOC directives as requests, not as commands for a signal change or movement Authority execution. The EVUs provide a field level check on the Movement requests and will deny it if a block or route segment is occupied or is scheduled to be occupied by a current Movement Authority.
Wireless communications is also supported via a three tier system composed of license-free 900 MHz frequency hopping radio network and a licensed long-range radio network in the railway allocated band.