Unit 4051 Introduction to Signalling Systems Assignment Brief
| Unit Number | 4051 |
| Unit Title | Introduction to Signalling Systems |
| Unit Reference Number | H/617/3667 |
| Unit Level | 4 |
| Credits | 15 |
Introduction
This unit aims to provide students with an underpinning knowledge of signalling, why signalling is provided, and also how it interfaces with other railway engineering disciplines and railway operations.
Students will consider different types of interlocking systems and which train detection systems are used in each type. An appreciation of railway operation will be given when discussing block systems as well as exploring the purpose of signalling from first principles, while considering the necessity for signals and their relationship within the modern railway.
The knowledge and understanding gained in this unit will enable students to make an informed choice should they choose to specialise in signal engineering or, alternatively, a thorough appreciation of the subject should they prefer to pursue other disciplines.
Learning Outcomes
By the end of this unit students will be able to:
LO1 Evaluate the meaning of signals and indicators provided on UK railways
LO2 Discuss the merits of various interlocking systems
LO3 Explore the necessity for train detection systems and how they are applied within the signalling system
LO4 Identify different types of block systems for single and double line railways.
Essential Content
LO1 Evaluate the meaning of signals and indicators provided on UK railways
The development of signals
- Historical background from hand signalling by ‘policemen’ to semaphore signals.
- Further development with the greater use of electricity
- First with power operation, then development of colour light signals in conjunction with more complex interlocking systems.
Signals in the cab
- The migration to cab signalling and indicators
- The case for removing wayside signals altogether.
LO2 Discuss the relative merits of various interlocking systems
The purpose of interlocking
- Historical overview, why it is necessary, what it achieves.
Mechanical interlocking
- Principles, use in conjunction with block systems.
Electro-mechanical interlocking
- Development from mechanical systems, greater use of electricity within interlocking and wayside signalling.
Electrical interlocking
- Types of relay interlockings, comparison with merits of earlier/later interlocking technology, ease of design, installation, test and subsequent modification.
Electronic interlocking
- Development of electronic interlockings, principles, management of data, interfacing with other systems, e.g. European Train Control System.
LO3 Explore the necessity for train detection systems and how they are applied within the signalling system
The origin of train detection
- Historical overview with early applications
- The difference between contacting and non-contacting systems, why it is necessary and what it achieves.
Application of track circuits
- Use in conjunction with the absolute block system and subsequent development of the track circuit block system with greater use of centralised control.
Communications Based Train Control (CBTC)
- Train detection using radio position reports sent from the train to the wayside equipment as used in moving block systems.
LO4 Identify different types of block systems for single and double line railways.
Block systems
- The difference between block systems required for train separation on single line railways and double line railways.
Single line railways
- Development from one train working through various systems (staff and token working to acceptance levers) to track circuit block.
Double line railways
- Development from time interval working through various systems (absolute block, track circuit block) to moving block systems.
Learning Outcomes and Assessment Criteria
| Pass | Merit | Distinction |
| LO1 Evaluate the meaning of signals and indicators provided on UK railways | D1 Critically evaluate the reasons for providing different controls for junction signals, considering the advantages and disadvantages of each. | |
| P1 Review the evolution of signaling technology from hand signalling through to cab signalling. P2 Assess the implications of cab signaling and indicators on wayside signalling. |
M1 Compare and contrast the difference between junction signalling using semaphore signals and colour light signals. | |
| LO2 Discuss the merits of various interlocking systems | D2 Compare the merits of relay interlocking with earlier/later interlocking technology, considering design, installation, test and subsequent modification. | |
| P3 Explore the development of the interlocking systems and the link between points and signals. P4 Determine the advantages and disadvantages between mechanical, electro-mechanical, electrical and electronic interlocking systems. |
M2 Assess the use of mechanical signalling in conjunction with block systems. | |
| LO3 Explore the necessity for train detection systems and how they are applied within the signalling system | D3 Investigate the differences between track circuits, train detection and CBTC detection, considering the benefits of each. | |
| P5 Explore the development of train detection systems and the application of track circuits. P6 Discuss the CBTC system and its importance in communicating the position of the train to the block system wayside equipment. |
M3 Assess the uses of train detection with respect to the interlocking and block systems. | |
| LO4 Identify different types of block systems for single and double line railways. | D4 Critically evaluate the differences between the track circuit block and moving block systems, in particular where application of each of the system would have advantages over the other. | |
| P7 Differentiate between the principles of the absolute block system and the track circuit block system. P8 Identify the main characteristics of electric token working for single line railways. |
M4 Produce control tables for aspect controls of a junction signal using the track circuit block system. | |
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