RPMI Railpen, the asset manager for the UK’s Railways Pension Scheme, has awarded a £700m (€832m) proprietary “stable momentum” factor investing mandate to Russell Investments.

The £22bn Railpen and Russell worked together on the strategy, with the resulting portfolio designed to mitigate the severity of momentum crashes, according to a statement from the external asset manager.

“This is achieved by looking beyond just the previous 12 month return and identifying those stocks that have not only strong returns but have also achieved these returns with a higher level of consistency,” said Russell in a statement.

“By identifying companies with consistently strong performance patterns it increases the likelihood of the returns persisting in the future.”

Craig Heron, senior investment manager at Railpen, said that the mandate is being added to the pension scheme’s alternative risk premia equity portfolio.

“We enjoyed working together to develop what we consider to be a robust approach to momentum investing,” he said.

Railpen made a push into alternative risk premia following an overhaul of its investment strategy in 2013, and in late 2015 grew its alternative risk premia team with a hire from EDHEC’s ERI Scientific Beta

In January this year, RPMI Railpen invested seed capital in multi-factor funds it created with Unigestion.

A concern with costs is one of the drivers behind the move into smart beta-style strategies.

Writing in the Railways Pension Scheme’s 2015 annual report, John Chilman, chairman of the trustee company, said that alternative equity premia strategies, through which the scheme’s equity investment has increasingly been carried out, “identify underlying drivers of return and build portfolios cheaply and systematically”.