Facebook now has over 1 billion worldwide subscribers, while Twitter has 200 million active users. A vast number of these "likers" and "tweeters" also use public transport which inevitably means they are instantly commenting on the services they use, good or bad.

I recently attended a social media workshop hosted by the International Public Transport Association (UITP) in Mechelen, Belgium, and the defining message from this event was that with social media now increasingly dominating communication, losing control of the message is a dangerous proposition for operators. As a result it is no longer a case of if an operator starts to use social media, but when.

"Social media does not exclude anyone," Mr Ciarán Rogan, marketing executive for Northern Ireland's Translink, told delgates. "You are on it whether you want to be or not."

Indeed in many cities where operators have yet to embrace social media, passengers have taken it upon themselves to set up their own pages dedicated to reporting performance. When Vienna's publically-owned transport operator, Wiener Linien, was embarking on its social media strategy, Ms Claudia Riegler, Wiener Linien's content manager for social media, said that she found 68 pages and feeds dedicated to its activities which were set up by so-called "co-creators."

"One even used the official logo," she says. "This had the potential to leave a bad impression."

The railway industry is perceived by many to have been relatively slow to pick up social media and explore the full advantages that it could provide. Many operators seem to have been deterred from engaging with some platforms through fear of doing a bad job or the cost of maintaining a responsive online presence.

However, some operators who presented their social media strategies in Mechelen are clearly doing an excellent job. Rogan believes that the more an operator puts into social media, the more they will ultimately get out in terms of improving their reputation and ultimately the quality of service provided to passengers. He believes that operators should "treat it as an opportunity" and not shy away from dedicating resources to social media.

"It shouldn't be a space for what we have not done, but somewhere where you are able to say what you will do," Rogan says.

He added that with Twitter and Facebook now driving the news agenda with photographs and video of news events appearing on the platform in real-time, well before media outlets are able to pick up and dissect them, transport operators have to equip themselves to react quickly. He says that Facebook in particular has been useful for Translink to state its official position on an issue before it gets out of hand, recalling its response to a recent picture of a rioter in Belfast who was wearing a Translink uniform. Rogan said that by responding to the incident immediately via Facebook, Translink was able to quell the impact of a potentially damaging story.

Providing accurate, consistent and quality information are all critical elements of a social media strategy, and one of the major challenges to using it as a communications platform. Rogan says a feed has to remain active and live. However, he says passengers do understand that they may not get an immediate response to their query outside office hours or at the weekend as long as an operator is clear from the beginning when the feed is staffed.

Paris Transport Authority (RATP), which began using a corporate Twitter feed in 2011, took a more pragmatic approach to using social media for public information. It launched four Twitter feeds for its services in September 2012 following a long and extensive development process which Mr Dominique de Ternay, RATP's head of marketing, says allowed the operator to build an online database of attractive information that can be used to answer passenger queries. Its presence has since grown to 15 separate feeds for individual metro, tram and RER lines, with each now boasting between 700 and 4400 followers.

In contrast, as an early starter with social media, Transport for London (TfL) took a step-by-step approach, allowing gradual growth as it, and its passengers, learnt how the different forms could be best applied. In 15 months it has gone from nothing to having dedicated Twitter feeds for each London Underground line as well as Overground services, a feed for the Oyster smartcard, a general TfL news feed, and feeds for bus and road traffic updates.

Mr Steve Gumbrell, TfL's head of marketing strategy and business management, says steadily ramping up its presence helped to avoid a "big bang" in costs while the operator has avoided hiring specific social media staff. Instead eight people from its customer service team have received training with 30 people overall able to post tweets on TfL's behalf. He says that it is an evolution of its customer relations strategy with Twitter in particular having a noticeable effect in reducing the number of calls to TfL's customer relations centres.

The training process for individuals using social media emphasises the tone of voice used in Tweets, guaranteeing accuracy, and how best to respond to certain complaints. This training also emphasises pacifying aggressive tweeters by presenting information in a positive but firm way. Staff are assigned to man zones rather than specific lines which Gumbrell says helps to provide relevant traffic updates to passengers who might be using more than one mode of transport in a particular area of the city.

Gumbrelll says that TfL established a Social Media Working Group to manage its strategy, which he describes as a loose coalition of representatives from different sections of the business. During its meetings discussions have focused on how social media can potentially save costs and be better applied. Decisions taken include dropping the robotic voice of early tweets in favour of a human presence.

The discussions also look at new ways of using social media, recently prompting an increase in the use of LinkedIn as a resource to post jobs, and using You Tube more to promote public information. Gumbrell says that discussions are continuing on the most effective way for TfL to use Facebook as a social media platform with its presence currently no more than a corporate page.

Mr Anatol Scholz, passenger and product marketing manager at DB Regio, says DB had similar reservations about its presence on Facebook, with a DB page seemingly coming across as conservative and not attracting many likes.

Its solution was to target specific niches in the market with campaigns rather than organisations. The result is the Bayern-ticket page which is targeted at passengers under 18-years-of-age in Bavaria and now has 57,000 likes.

"We decided to launch the Bayern-ticket page around the time of the Chiemsee Reggae Summer festival which is very popular with young people, and was a way of attracting a core group of followers from the start," Scholz says.

He added that the emphasis on the Bayern-ticket page is on "fun," because fun things are what draw engagement. For instance a white sausage with a caption of "typical Bayern" drew 408 likes and 64 shares. A quick scan of the Bayern-ticket feed also shows that the emphasis is on young people having fun in Bavaria, rather than the train service itself which is presented as the enabler for a good time.

Wiener Linien similarly emphasises fun in its posts, and Riegler says Facebook is now the company's primary social media portal, with around 32,000 current likes. She says that like the Bayern-ticket page, not all posts are about the service itself, but about things that are taking place in Vienna which can build loyalty and expand the public's view of Wiener Linien as being more than just a transport operator.

This approach is shared by RATP, which posts on its Twitter feeds about leisure activities and specific events taking place in Paris, while São Paulo transport authority's BOM card is marketed as a ticket to free and fun activities in the city. It provides a reason for people to travel through its related social media sites which promote events and offers information relevant to the area.

Clearly railway operators are still testing and developing their social media marketing strategies and many more successful ways of reaching out to social media users are seemingly yet to be discovered. Yet the rewards are potentially very attractive. A Twitter survey, or "Twervey," conducted for TfL found that 72% of people believed that its activities on Twitter had enhanced its reputation, while 81% check the feeds at least once a day and have changed their travel plans as a result.

Creativity certainly seems to be the secret to becoming successful on social media success and taming marketing's new frontier. But as they do, Scholz warned that they should not lose sight of their overall strategy, and to avoid doing too much too soon. "Be easy going, relevant and above all keep it simple," he says. "And at the same time be prepared for the hard questions."