RailNet AEI System – Introduction

What is AEI?

The Automatic Equipment Identification (AEI) system automatically collects and transfers electronically coded information from rolling equipment to a host computer management system. Train identification involves acquiring railcar axle and tag data from trains passing the site. The APU-102 and other AEI site components are employed to acquire the axle and tag data of the trains that passed the site. 

As the train passes the site, the APU-102 senses train presence, direction, and speed via the wheel detectors and decodes the tag data via the radio-frequency identification (RFID) subsystem (see The Hardware section below). When it receives the axle and tag data, it combines the data to create a clean consist - a list of the all cars and locomotives on the train. Within seconds of the train passing the site, the APU-102 delivers the clean consist to the host system. At the host system it can be reviewed and manipulated by the user.

APU-102 Overview 

The APU-102 was developed during the infancy of railroad AEI and has been under constant evolution, both hardware and software. Much of the hardware and software changes are co-dependent. 

The Hardware

The hardware is detailed later in this text. The original APU-102 was designed around a 286-AT class processor. The software development quickly outgrew the 286 and there are no longer any 286 APU-102s in use. Next came a 486SX based processor on a 486SLC board. To track different configurations of the APU-102, including CPU type, suffixes were added to the APU-102’s serial number. The 486 was noted with an “E”. Throughout this manual, you will see references to the APU “Series” (E Series=486). The P Series APU-102 uses a Pentium processor, board designation is LPMTX. The current processor, L Series, is an AMD chipset and the board is designated LX-800.  

The Software

All versions present a consistent user interface. However, the available commands and features differ between versions (later versions may provide new features and drop certain commands no longer needed). Sections of the manual that are specific to certain versions are noted when possible but, generally, most sections apply to all versions. 

See RailNET Software for details about the current supported versions of the software.

APU-102 Operation

The Auxiliary Processor Unit (APU-102) is the central component of the AEI system’s data acquisition process. The APU-102 identifies train equipment using an axle acquisition subsystem and an RFID subsystem. In the axle acquisition subsystem, the APU-102 receives axle data through rail-mounted wheel detectors. Wheel detectors (or “wheel transducers”) identify initial train presence, train movement, and speed. The APU-102 uses the RFID subsystem to read electronically coded tags mounted on the side of locomotives, railcars, trailers, and end-of-train (EOT) units at speeds up to 79 mph. The APU-102 stores all tag data, including time and date, train direction, and speed through the AEI site. The information is stored by train sequence and can be reviewed through local or remote access. 

Methods and equipment used to acquire axles and tags may vary depending on site setup; however, the AEI system process of acquiring train data always involves some form of these two subsystems. 

Axle Acquisition Subsystem

Wheel detectors are the main component of axle acquisition. They determine initial train presence and train direction and speed by identifying wheel events (or axle count) for the passing railcar. Components of this subsystem include one or more wheel detectors, proper cabling, a wheel detector interface card, and a track directional analyzer in the APU-102. Since wheel detectors depend on train movement to detect presence, a presence circuit must be employed to keep the session open when a train has stopped at the site. The presence circuit may also be used to establish initial train presence, as a wheel detector would. 

RFID Subsystem

The RFID subsystem employs RF technology to receive and transmit train information to the APU-102 from the electronically coded tags mounted on each railcar and locomotive. Components of this subsystem include an AR2200 RF unit, AI1200 reader logic board, one or more antennas, and an RFID tag. 

Descriptions of the subsystem components and AEI system operation appear later in this manual. Refer to the Train Processing Block Diagrams for a graphical overview of APU-102 operation.