Maintaining the correct temperature and humidity in areas of the museum where unique historical railway documents and artefacts are stored is a vital part of their ongoing conservation. Tinytags are constantly monitoring these unique archives.

Barrow Hill is the last remaining operational railway roundhouse in the UK. In addition to an ever-changing collection of steam, diesel and electric locomotives, it also houses a small but unique collection of historical items relating to Barrow Hill and the surrounding railways, including documents and railway items.

Whist some items are in excellent condition, others have been subject to a life outside and they have started to deteriorate. With limited resources available, the conservation team was faced with a quandary of whether to restore the items or to allow a slow but natural deterioration. It has opted on the last course for authenticity, and the key task is to delay as much as possible the onset of time. This is made even more difficult as the collection is housed in a grade two listed building which is either cold and damp, or hot and dry, according to the season. There are tight guidelines to achieve the requirements, and the team has an environmental control unit to help control the humidity - the biggest problem.

A Tinytag Ultra 2 temperature and relative humidity logger, located within the archive collection shelving provides constant monitoring. It has been carefully positioned to avoid being too close to the environmental unit and away from direct sources of heat and ventilation. It provides recordings at six minute intervals and if required, is able to monitor for three months without being reset.

As part of Barrow Hill's requirements as an Accredited Museum, evidence must be produced that the collection is constantly monitored. Data is examined on a weekly basis and graphs produced monthly.

Mike Creagh, a volunteer in the museum's archives, comments, "Using the Tinytag, we are able to quickly react to situations when it becomes clear that our heating or de-humidifying units require adjustment because of the seasons. In one occasion we noted that the overnight temperature and humidity was well outside what was considered desirable and action was taken to resolve the problem.

"Key reasons for choosing the Tinytag were its simplicity and its ease of use. It gives us the results in a format that is easy to read, and react to. As with any volunteer run organization a major problem is making sure that all staff can understand and use it for the sake of continuity. We have it re-calibrated every year which gives us confidence about accuracy."