Pictured: The front page of the Inspire magazine published by al-Qaeda

Propagandists for al-Qaeda have urged their followers in the West to commit mass murder by derailing 'vulnerable' trains with a homemade tool.

The Islamist terror group laid out its plan in an article titled 'Train Derail Operations', which was published in the latest issue of its magazine Inspire.

Would-be murderers are told: 'It is time we instill fear and make them impose strict security measure to trains as they did with their Air [sic] transportation.'

The elaborate 19-page tutorial uses the United States as an example target but stresses that the UK and France also have long stretches of unguarded railways.

In the article, the author explains that the motivation for targeting trains is so that Islamist terrorists might 'continue to bleed the American economy to more losses, increase the psychological warfare and make it worry, fear and weaken much more'.

An official US body is also cited after it highlighted more than 100,000 miles of vulnerable American railways and worries over hazardous materials being transported along them.

Included in the lengthy guide are step-by-step instructions on how to create a 'homemade derail tool' and where best to position it to cause maximum damage.

Followers of the group - al-Qaeda in the Arabian Peninsula - are urged to study schedules and time the deployment of their obstacles to match certain trains.

In 2004, terrorists linked with al-Qaeda murdered 191 in Madrid, Spain after planting ten bombs on commuter trains. Pictured: The scene of the attack in Madrid

They even included a map of US railways and highlighted busy passenger routes.

Because it would not require the 'martyrdom' of the attacker, the Inspire article stresses that a single follower could derail several trains in repeated attacks.

The magazine also warns Muslims in the West to reject 'the message of solidarity' from political parties or other groups - and even from a 'kind neighbour or a nice co-worker'.

It adds: 'The West will eventually turn against its Muslim citizens'.

Just hours after the publication of the magazine online, the New York Police Department's counter-terrorism department responded on Twitter.

They said they were already aware of the threats from al-Qaeda before they released the issue and stressed that their 'robust' defence apparatus was designed to protect railways.

In 2004, terrorists linked with al-Qaeda murdered 191 in Madrid, Spain after planting ten bombs on commuter trains.