factors. In particular, it was a radicalbut ‘lean’ design that was dedicatedto an over ambitious requirement,i.e. too high a speed of 250 km h-’speed, new non-hunting bogies, upto 9” of powered tilt on curves, andnew lightweight passenger coaches ina fixed configuration. The HST,which was also developed during thesame period as the APT, was a moreevolved conservative design withlower performance specifications andmuch more operational reliability(freight and passengers) and flexibleuse for both the coaches and locomo-tives. BR has learned many lessonsfrom the APT and HPT trains and isbeginning to apply them in whatlooks to be a more ‘robust’ designconfiguration for the InterCity 225which will allow it to be used fordifferent markets and different pur-poses. The InterCity 225’s Class 91‘Electra’ power car is a conventionalseparate locomotive which can beused not only for seated passengertrains but for sleepers, parcels andfreight. The Mk4 coaches are anevolved design of conventional steelcoaches and not the APT aluminiumcoaches. The APT lightweightcoaches had ride and vibration prob-lems which if solved with aluminiumtype construction would have re-sulted in coaches of heavier construc-tion than those made of steel. Foreast coast operation (late 1989) thecoaches will be non-tilting becausethey contribute very little to journeytimes on that route. Once this hasproved successful, tilting versionswill be developed for the west coastroute where they can contribute to areduction in journey times. OverallBR has done a much more detailedreview of market and operationalrequirements of its fast long distancetrains in the nineteen nineties. It isencouraging to see an organizationsuch as BR learn from both its

innovative successes and failures andto produce a ‘robust’ design briefthat meets a broad range of presentand future requirements. StephenPotter’s book is an optimistic storyabout the practical limits to tech-nological innovation which stillallows for progress and change.

Paul Gardiner

Computers and peopleAnn Majchrzak, Tien-Chien Chang,Woodrow Barfield, Ray Eberts and Gav-riel Salvendy, Human Aspects ofComputer-Aided Design, Taylor and Fran-cis, Philadelphia and London, 1986. 278pp. ) x25.00.

This team of authors at PurdueUniversity, Indiana, has producedan excellent book which integratestechnical information about CADwith human-computer interactionand the effects and management ofchange from manual to CAD proce-dures in the design office.

There are some signs that therecent passionate honeymoon periodof CAD use is cooling, as manage-ment finds that the promised pro-ductivity of CAD does not material-ise. This book is therefore timely andis relevant to those who are about toinstal CAD systems as well as tothose who have to use them. Thebook aims to make a positive con-tribution to the effective design,implementation and use of CADsystems.

It is divided into three main parts.Part 1 is concerned with the techni-cal aspects of CAD. These includenot only the usual hardware andsoftware aspects but also system-to-system interfaces. Expert systemsand the future development of CADtechnology are also briefly covered.This is a good introduction to thetechnical side of CAD, presentedclearly and succinctly, with helpful

illustrations.Part 2 addresses the human-

computer interface problems. Theseinclude familiar matters of the ergo-nomics of workstation design andhuman-computer interaction. Theauthors review relevant and up-to-date research in interface design,including aspects such as health.(For example, although copy typistsand people with similar repetitivetasks report eyestrain, headaches,etc. when using VDUs, it seems thatthis is not the case for CAD systemoperators.) Cognitive and perceptualaspects of CAD, including decisionmaking and problem solving, arereviewed in similar ways.

Part 3 is concerned with the man-agement of CAD. It continues thereview of research in areas such asthe threats of job loss, of deskillingand routinization of work with CAD.In general, the case seems to be ‘notproven’ - we don’t have a great dealof information yet, but there is littleevidence of the worst fears comingtrue. This part of the book concludeswith advice on how to manage theprocess of implementing a CADsystem. Finally, there is a brief set ofconclusions on the effective designand use of CAD.

This book is relatively unusual inconsidering the technical and socialissues of CAD side-by-side. If youwant to know about CAD and itseffects then this is the starting place,with a wealth of references to followup in more detail if you wish. Re-commended not only for researchersbut also for the many designers whoare faced with computerization - andtheir office managers. The mainmessage is that it is not CAD as suchthat causes problems, but the man-agement context in which it is intro-duced .

Nigel Cross

120 DESIGN STUDIES