The process was handled directly by the charity. There was no incumbent on the business.
The agency will be tasked with raising awareness of the suicide prevention programme, which is funded by Network Rail.
The campaign will aim to bring down the number of railway suicides and improve the support to those affected by such events. It will target high risk groups including middle-aged working class men.
Samaritans wants vulnerable people to seek help if they are finding it hard to cope, and is looking for the campaign to raise awareness of the services it provides.
Paul McDonald, the executive director of communications at Samaritans, said: "As we begin to implement our new six-year strategy, we are poised to push Samaritans’ brand forward and raise awareness of our vital services among high risk groups in particular.
"I am delighted to have DLKW Lowe on board to help us achieve this, by creating a dynamic campaign, which will capture people’s attention and, crucially, encourage help-seeking behaviour among those who need it most, no matter what they are struggling with."
DLKW Lowe will also work on other strands to raise awareness of the charity as part of the one-year contract.
Kate Snowden, the head of media campaigns at Network Rail, said: "We’re committed to reducing the number of suicides on the railway and the trauma that they cause not only to the families involved but to railway staff and passengers who are affected.
"We’re looking forward to a fresh and innovative campaign that will increase awareness of this important issue."