Feature: Rail
cellular communication, which enhances the efficiency of carriage-to-carriage and train-to-ground communications and enables over-the-air updates to firmware and soſtware. Tis technology not only allows operators to provide passengers with secure and environmentally-friendly transportation whilst offering appealing onboard multimedia services, but also facilitates communication to station-based signage and cloud storage infrastructure with critical system information.
Rolling stock standards RCS, or Rail Compliance Standards, are implemented to ensure that all electrical equipment on rolling stock or railways adhere to strict safety regulations. In particular, EN50155, EN50121 and EN45545 are important standards in Europe and the UK that regulate railway equipment in parameters that include ruggedness, electromagnetic compatibility and fire safety.
EN50155 for onboard systems Tis standard regulates heat, shock and vibration resistance, as well as the quality of the power supply – a critical component in trains and adjacent equipment. Systems must be operable over a wide temperature range, given the industrial nature of the railway, and the EN50155 standard distinguishes the temperature ranges in a number of temperature classes, listed in Table 1. In addition to heat, it’s also important
that onboard devices accept a wide voltage range, since many rail-approved devices require 24V-110V. Tis wide DC power range ensures that a computer system can
M12 connectors, named after their metric thread size of 12mm, are a type of circular electrical connector commonly used in railway applications because they meet the criteria specified in EN50155
support the wide variety of rolling stock used in the UK today, and removes the need for separate, and oſten expensive, railway-approved DC-DC converters. It is imperative to use ruggedised
equipment that can perform in extreme environments over extended periods, especially considering that vibration and humidity are ever-present in the railway environment. Corner bonding, underfill and conformal coating are solutions that can ruggedise embedded PCs. Corner bonding and underfill create
a strong bond between the PCB and its components, sealing them together with fewer gaps, helping to prevent damage in environments with high levels of shock and vibration, whereas corner bonding only seals the corners of the component, and underfill covers each edge for a complete seal, which is then cured with UV light. Conformal coating can be made from
various materials, including acrylics, silicones, urethanes or epoxies, and protects the circuit board from harsh operating conditions and environmental factors, helping to keep moisture at bay and making water damage less likely. While this can’t guarantee IP-rating conformity for water resistance, it can help to strengthen the circuit board considerably for industrial purposes. M12 connectors, named aſter their
metric thread size of 12mm, are a type of circular electrical connector commonly used in railway applications because they meet the criteria specified in EN50155. Te connectors are designed to withstand the harsh environmental conditions associated with railway operations, including temperature variations, moisture, vibration, shock and mechanical stress. Te lock and seal mechanism on M12 connectors means they do not come loose with vibration and prevent dust and water ingress, which is particularly important when considering the many I/O ports featured on railway embedded computers. X-coded M12 connectors and cables
can also improve Ethernet data speeds for railway applications, as these are designed to perform up to 10GB/s compared to D-coded cables, which do only to 100MB/s. Tis is achievable because X-coded cables have an 8-pin configuration that is designed to support high-speed data transmission versus D-coded cables’ 4-pin configuration. Te higher data transfer rates and 8-pin configuration of X-coded cables make them preferable for a range of onboard applications where fast and reliable communication is crucial.
Table 1: The EN50155 standard splits the temperature ranges in several classes
EN50121 Another essential railway standard is EN50121, which relates to the electromagnetic compatibility (EMC) of electronic and electrical systems within railway applications. Complying with this standard helps prevent interference issues and maintain the reliable and safe operation of railway infrastructure and rolling stock. Tis ensures that all systems can operate together without being susceptible to electromagnetic disturbances.
42 July/August 2024
www.electronicsworld.co.uk
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72
