This article begins with a dreadful tale of disaster on the railway that was caused simply by people not paying attention to what they were doing.

Head-on collisions on single-track stretches of railway are the most horrific of accidents because the speed of both vehicles involved is effectively doubled on impact. The evolution of the railways has seen some terrible calamities over the years, and yet after each one, lessons were learned and improvements in safety followed. One such development was so successful at controlling the traffic that ran both ways along a single track that it was considered fail-safe. Yet the assumption that the system was foolproof was a major factor in proving, with terrible violence, that it was not. The system had worked very well for a number of years and this had allowed laxity to creep in as drivers and signalmen became convinced that a head-on collision on a single stretch of track was now impossible. But, as we all know, if something can go wrong, it will, and what went wrong at Abermule in Wales on 26th January 1921 was of enormous magnitude.

The system involved the issuing of tablets, which were inscribed with details of the stretch of track it allowed the driver to go along. There were instruments at stations either side of the stretch of single track and these were electronically connected in such a way that every time a tablet was issued the system was locked and no other traffic could proceed along that stretch until the tablet had been placed back into the instrument at the other end, and without this tablet the driver could not proceed. The tablets were kept in leather pouches and each time one was handed to a driver he was duty bound to check that he had been given the correct one for the stretch of track ahead. But because drivers had become so used to the smooth running of the system, and they believed in its infallibility, they often neglected this duty. One busy night an inexperienced young station hand became confused and he handed a tablet to the stationmaster, who then mistakenly handed it to a driver, who did not check it. This short chain of errors allowed the train to pull away and only a few minutes later it was discovered that a mistake had been made and the train should not have been allowed to go on its way. As concerned staff gathered on the platform to discuss the matter, a distant screaming whistle was heard, followed by a deep rumble. The train had crashed head-on into another with the loss of 17 lives.

All of which goes to demonstrate that sometimes a momentary lapse in concentration can bring catastrophic results. And after the high drama of railway disaster, we come to the more sedate world of Microsoft Outlook, where the same rule applies and not paying attention to the job in hand can have undesired consequences. Here are a couple of examples.

One of your associates struck it big on the lottery and walked out of his job. You need to remove his details from the distribution group. To remove him from the list select his name. At this stage you might think that by hitting Delete he would be removed, but doing this would delete the entire list. You should use the Remove Members button to delete the selected members (this is just called Remove in older versions of Outlook). If you do accidentally delete the entire list, find it in the Deleted Items folder and drag it back into your Contacts folder.

All junk mail, whether paper or electronic, is a pain in the neck. Disgruntled householders often use the ploy of sending paper junk back to the place it came from, thus costing the company postage. You may think that a similar ploy would work for spam emails, and they could be sent back to the sender with a click and a cry of 'That'll teach 'em'. But it is not advisable to do this as it only serves to show the sender that your address is valid and more unwanted mails could be the outcome. It is far better to grin and bear it, and delete all unwanted mails.

So, whether you are dealing with unwanted emails or great steaming locomotives with carriages packed with people, it is important to pay attention to the job in hand at all times. Allowing laxity to slip in can lead to errors that could knock your whole day off the rails.