Radio frequency communication and fault detection for railway signalling

The continuous and swift progression of both wireless and wired communication technologies in today's world owes its success to the foundational systems established earlier. These systems serve as the building blocks that enable the enhancement of services to cater to evolving requirements. Studying the vulnerabilities of previously designed systems and their current usage leads to the development of new communication technologies replacing the old ones such as GSM-R in the railway field. The current industrial research has a specific focus on finding an appropriate telecommunication solution for railway communications that will replace the GSM-R standard which will be switched off in the next years. Various standardization organizations are currently exploring and designing a radiofrequency technology based standard solution to serve railway communications in the form of FRMCS (Future Railway Mobile Communication System) to substitute the current GSM-R. Bearing on this topic, the primary strategic objective of the research is to assess the feasibility to leverage on the current public network technologies such as LTE to cater to mission and safety critical communication for low density lines. The research aims to identify the constraints, define a service level agreement with telecom operators, and establish the necessary implementations to make the system as reliable as possible over an open and public network, while considering safety and cybersecurity aspects. The LTE infrastructure would be utilized to transmit the vital data for the communication of a railway system and to gather and transmit all the field measurements to the control room for maintenance purposes. Given the significance of maintenance activities in the railway sector, the ongoing research includes the implementation of a machine learning algorithm to detect railway equipment faults, reducing time and human analysis errors due to the large volume of measurements from the field

An investigation of the propagation of radio waves at frequencies in the VHF and UHF bands within certain British cities

Unmodulated carrier waves at frequencies of 75.375, 85.875, 167.2 and 441.025 MHz have been radiated by aerials mounted on tall buildings or prominent terrain features in the British cities of Birmingham, Bath and Bradford. The spatial distribution of the r.f. signal envelope existing within urban and suburban areas at these frequencies has been recorded using a vehicle-mounted receiver with a aerial fixed to the vehicle's roof. An analysis of these measurements has shown the distance over which the envelope may be anticipated to be Rayleigh distributed to be less than 75 m. A median signal prediction model is derived from the measured data and its performance is statistically assessed with the experimental values. The measurements and the predictions have been found to be·in close agreement. Comparison of the Okumura model with measured values has demonstrated that the proposed model exhibits similar prediction errors to those obtained by the more widely used Okumura model. The Okumura model is therefore concluded to be more complex, and hence more costly to use, than is necessary for applications in British cities

Bowdoin Orient v.61, no.1-27 (1931-1932)

https://digitalcommons.bowdoin.edu/bowdoinorient-1930s/1001/thumbnail.jp

Bowdoin Orient v.69, no.1-26 (1939-1940)

https://digitalcommons.bowdoin.edu/bowdoinorient-1940s/1010/thumbnail.jp

Bowdoin Orient v.69, no.1-26 (1939-1940)

https://digitalcommons.bowdoin.edu/bowdoinorient-1930s/1010/thumbnail.jp

Bowdoin Orient v.62, no.1-27 (1932-1933)

https://digitalcommons.bowdoin.edu/bowdoinorient-1930s/1002/thumbnail.jp