Software intensive Systems Engineering 1997/98
Coursework specification
Objective
The objective of this coursework is to give you some experience of the practical
difficulties of software-intensive system design.
System description
The Lancaster Light Railway (LLR) is a transportation system which is planned to help
address Lancaster’s chronic traffic problem. The goal of the system is to drastically
reduce the number of commuter car journeys in the Lancaster area by providing an
efficient city-wide public transport service. The system operates around 2 loops one to
the north and one to the south of the river with a single connecting station by a river
bridge. Therefore, to travel to the University from Morecambe, passengers would take
the Northern loop to the connecting station then change to the southern loop for the
journey to the University. A continuous shuttle of driverless trains runs on each of
these loops.
This system can only be operated cost-effectively if it is a completely automated system
with driverless trains, automated ticketing, etc. The goal of this particular exercise is to
carry out an initial high-level system design for the train control system which provides
for driverless train operation.
You are required to write a short report suggesting a possible architecture for the train
control system. This report should be structured as follows:
1. Introduction (1 page) This should describe the problem to be addressed and discuss
how a light railway system can make a useful contribution to the problem.
2. Problem description (1 page) This should give an overview of the problem of train
control (see later information). You should not simply reproduce the list of essential
features but should abstract from them to present the key problem characteristics.
3. Solution alternatives (2 pages) You should describe at least 2 and at most 3 possible
ways of implementing the essential features of the train control system
4. Solution recommendation (1 page) You should choose one of the solution
alternatives which you have identified and justify your choice of solution.
5. Architectural model of the system (2 pages) This should include a block diagram
which identifies the critical sub-systems in the train control system and a brief, one
paragraph, description of each of the sub-systems.
The sizes for each section that I have recommended are maximum sizes i.e. you don’t
have to write a full page if you can express your ideas in less space. You should
assume that you are writing the document for a review panel which includes people
from a variety of backgrounds. You may assume some general knowledge of system
engineering but not detailed knowledge of either transport engineering or software
engineering (i.e. you can’t assume that the readers will understand the concept of
object-oriented systems, for example).
The work should be handed in to Cath Ewan by the beginning of week 6 i.e. Monday
16th February at 11am.
You may find the following information helpful in completing this assignment
Train control systems
Driverless train control systems have already been implemented in a number of urban
transport systems. The train control system is an on-board system which is mounted on
all trains and which communicates with a central control room which monitors train
positions, speeds etc. Depending on the technology used to implement the system,
controllers in the central centre may have differing levels of commands that they can
issue to a train. These range from a complete override of all train control system
functions (including functions to speed up or slow down the train) to a simple stop/start
function which simple either stops or starts the train.
The train control system is interfaced to a separate computer-based system for door
control (opening and closing doors) and to the light railway signalling system with
signals controlling each segment of track. The signalling system can communicate with
the train control system at any point in the system. Trains always receive signalling
information when they enter a segment of track.
The train control system must provide at least the following functions:
1. Control the speed of the train as it moves between stations.
2. Bring the train to a halt at stations and indicate to the door control system that the
train is stopped at a station.
3. Start the train moving from rest either from a station when the door control system
indicates that all passengers have boarded the train or between stations on command
from the signalling system.
4. Control the train brakes and, in particular, bring the train to a halt if:
the power to a track segment is cut
signalling information is not received on entry to a track segment
the train encounters an obstruction on the line
a signal is received from the signalling system to stop the train
a passenger on board the train pulls the train comunication cord
5. Communicate the speed and the identifier of a train at regular intervals to the central
control room.
URLS which may be useful
http://www.dlr.co.uk/tech.htm
http://www.well.com/user/bartmail/Times/July-96/close.html
http://www.geharris.com/
http://www.jle.lul.co.uk/index.htm
http://www.adahome.com/Ammo/Success/train.html
http://www.gfocus.com/train_trac.html
You should not rely solely on the information available in these URLs. You are
strongly recommended to carry out your own research of web-based material on this
topic. As well as train control systems, you may find information about automated train
protection systems helpful.
These URLs and other information about the work which may emerge from questions
can be accessed through the Intranet coursework page for this course
http://info.comp.lancs.ac.uk/year2/CSC223-SISE/cwork.html