The party warned that the threatened stoppages from November 1-12 risked “completely overshadowing” the two-week climate change conference in Glasgow which starts on October 31.
It came as the Rail Maritime and Transport union (RMT) today formally rejected a 4.7 per cent, two-year pay deal – nearly two weeks after the offer was made.
ScotRail said the lack of such official notification had hampered further attempts to resolve the dispute.
It said it would be able to run less than 10 per cent of normal services if the strikes went ahead, with trains on the Edinburgh-Bathgate-Glasgow line expected to be the only ones operating outside the Glasgow area.
A similar skeleton service has been running on Sundays since March, which is due to continue until at least November 28 as part of a separate RMT dispute over payments for working on days off.
Network to ‘grind to a halt’
ScotRail has had to postpone announcing plans for increased services during COP26 because of the strike threat.
Scottish Conservatives transport spokesperson Graham Simpson said: “These strikes are threatening to completely overshadow the COP26 summit.
"At a time when we should be encouraging people onto public transport, Scotland’s rail network is going to grind to a halt.
“SNP ministers hold the purse strings and should never have let it reach a stage where this dispute hasn’t been resolved a matter of days before world leaders descend on Glasgow.
“But there is also an onus on all parties to get back round the table and urgently come to an agreement.”
Neil Bibby, his Scottish Labour counterpart, said: “The Scottish Government’s failure to properly engage with trade unions from the outset has contributed to this long-running and difficult dispute.
"I hope the dispute can be resolved and that the Scottish Government and ScotRail will rebuild industrial relations on Scotland’s railways after months of discord and decline on their watch.”
RMT Scottish organiser Mick Hogg said the offer was “not acceptable” but the union was available for further talks “morning, noon or night”.
However, he said a deal was still needed on “rest day working” – extra payments for working on days off.
The union is angry that train drivers are paid more for this, because a shortage of drivers remains due to delayed training caused by the Covid pandemic.
That arrangement is to be continued for a further year.
Mr Hogg said: “If the authorities do not see sense, it’s curtains – and full steam ahead [to industrial action].”
A ScotRail spokesperson said: “It’s extremely disappointing that the RMT has opted to continue with this highly-damaging strike action.”
Among ScotRail’s other unions, the results of a ballot of Transport Salaried Staffs Association office staff members on the 4.7 per cent offer is due by Thursday.
A similar ballot among engineering staff, represented by Unite, is due to be completed on Monday.
Aslef has accepted a 2.2 per cent, six-month pay deal for train drivers, and the 4.7 per cent, two-year deal for shunter drivers.
A Transport Scotland spokesperson said: "In the interest of collective bargaining, we understand that ScotRail would need to re-engage all four unions to determine the next steps.
“We are keen to see this issue resolved ahead of COP26 so everyone who works in Scotland’s Railway can play their part in welcoming the world to our country.”