LEADERS of the train drivers' union Aslef may mount a legal challenge to last week's election result which saw general secretary Lew Adams ousted in favour of a member of Arthur Scargill's hard-left Socialist Labour Party.

Leeds train driver and union official Dave ''Mickey'' Rix , 35, defeated ''old'' Labour stalwart Lew Adams by 4558 votes to 3357 in a result which could signal increased militancy on the privatised railways.

Instead of ratifying the result yesterday, the Aslef executive merely noted it and instructed assistant general secretary Tony West to investigate whether there had been any irregularities before reporting back as a matter of urgency.

Although the moves are shrouded in secrecy and were neither confirmed nor denied by the union, The Herald understands that there are two main areas being looked into to see whether Aslef rules were breached.

One concerns complaints that Mr Rix had been given up to three months' sick leave because of ''back problems'' by his employers Regional Railways North East during which time he toured the UK electioneering, including holding meetings in Scotland, Bristol and Manchester.

RRNE is a subsidiary of Liverpool-based MTL which cancelled a proposed Stock Exchange flotation in February because of a wave of industrial unrest affecting its Merseyrail Electrics subsidiary.

The other main cause for concern centres on unofficial election circulars attacking Mr Adams, which appeared over the election period.

There is also some suggestion of possible interference by SLP supporters from the rival Rail, Maritime and Transport union.

In accepting defeat last week, Mr Adams, whose current term of office runs until next January, said he was disappointed to have lost the election, particularly to a candidate who is a member of the SLP and who, he suggested, had ''obviously had a lot of resources behind him''.

Meanwhile, South West Trains is facing a series of one-day strikes over the Bank Holiday period in a row over the role of guards.

The RMT has called for walkouts on May 22 and 26 - either side of a Bank Holiday weekend - and on June 1 even though the company, owned by Perth-based Stagecoach and operating out of London's Waterloo station, withdrew proposals to ''revise'' the role of guards.