This paper presents a full-scale test on a railway bridge located in the northern part of Sweden. The reason why the bridge needed to be strengthened was insufficient bearing capacity due to increased loads on the railroad system. The problem was mainly low moment bearing capacity in the bridge cross direction. A total of 3200 meter of carbon fibre sheets with the width of 0.3 meter was applied to the bottom face of the bridge. A comprehensive testing program was formed for the bridge. Strains and deformations were measured before and after strengthening. The measurements from the test program showed that the bridge stiffness increased by approximately 15%. This means that the method works in fall scale and can be an economic way to extend the life of concrete railroad bridges. To investigate the influence of change in humidity over time due to the tight composite layer, measurements over at least one year will be undertaken. Up to now the preliminary results show no effects of raised humidity under the composite layer.