Commuters board a Metra train on the Union Pacific Northwest line in Barrington on March 16, 2020. (Stacey Wescott / Chicago Tribune)

Update: Tentative railway labor deal reached, averting strike, President Joe Biden says. Read more here >>>

As government and business officials brace for the possibility of a national freight railroad work stoppage, Metra and Amtrak warned of service changes beginning Thursday.

Amtrak said Wednesday it was canceling its remaining long-distance service, days after it suspended service on several routes out of Chicago. Amtrak also suspended some local service Thursday night, including routes between Chicago and downstate Illinois, St. Louis and cities in Michigan.

Metra said service on its BNSF and Union Pacific North, Northwest and West lines would stop Thursday night, as the BNSF and Union Pacific freight railroads that own and operate those lines have said they will begin cutting back service in preparation for a potential work stoppage. If a strike or lockout were to take place, service would also be canceled Friday on those commuter rail lines.

Other Metra lines interact in other ways with the freight railroads, but Metra said it expects to be able to run scheduled service Friday on some of them. Those include the Metra Electric and Rock Island lines — its only two lines that do not interact in any way with freight railroads — as well as the SouthWest Service and Milwaukee District North and West lines.

The commuter rail service said it was continuing to talk with the freight railroads that interact with Heritage Corridor and the North Central Service to determine whether Metra could run trains on those lines.

A Metra train from Chicago arrives the Brookfield station on the BNSF Railway Line on Dec. 10, 2018. (Zbigniew Bzdak / Chicago Tribune)

Federal law bars a freight railroad strike or lockout before Friday, and Congress could intervene and block a work stoppage if the unions and railroads can’t reach a deal by the end of the week. But freight and passenger railroads have begun taking preemptive steps.

Amtrak’s cancellations, which began Tuesday, were intended to avoid possible disruptions should the freight railroad workers walk out while lengthy passenger train trips are underway. Nearly all of the passenger service’s routes outside the Northeast U.S. run on track that is owned, maintained and dispatched by freight railroads, and a walkout could disrupt passenger service.

The freight railroads also said they would begin curtailing shipments of hazardous materials and other chemicals Monday to ensure carloads of dangerous products won’t be stranded along the tracks if the trains stop moving. The heads of the Sheet Metal, Air, Rail and Transportation Workers — Transportation Division union that represents conductors, and the Brotherhood of Locomotive Engineers and Trainmen union that represents engineers, criticized that decision as a move to increase pressure on shippers and Congress to intervene.

Business groups and government officials are bracing for the possibility of a nationwide rail strike that would paralyze shipments of everything from crude and clothing to cars, a potential calamity for businesses that have struggled for more than two years because of COVID-19 related supply chain breakdowns. The Association of American Railroads trade group put out a report last week estimating that shutting down the railroads would cost the economy $2 billion a day.

The majority of the unions representing some 115,000 freight rail workers had reached tentative agreements needed to avert a strike at the nation’s biggest freight railroads, including Union Pacific, BNSF, Norfolk Southern, Kansas City Southern and CSX.

But Wednesday, members of one of the unions whose leaders had reached a tentative deal rejected the agreement, though they also agreed to delay any strike by members until Sept. 29 to allow more time for negotiations and to allow other unions to vote.

Members of two other unions ratified agreements. Ratification votes by other unions remained pending, while some groups remained at the bargaining table.

The tentative deals that were reached closely followed recommendations by a Presidential Emergency Board that called for 24% raises over five years, $5,000 in bonuses and one additional paid leave day a year.

The key unions that represent the conductors and engineers who drive trains are holding out in the hope that railroads will agree to go beyond those recommendations and address some of their concerns about unpredictable schedules and strict attendance policies that they say make it difficult to take any time off. They say the job cuts major railroads have made over the past six years — eliminating nearly one-third of their workers — have made a difficult job even harder although the railroads maintain their operations have just become more efficient as they rely on fewer, longer trains.

The unions want the railroads to provide unpaid leave time that workers could use to attend doctor appointments or attend to other personal business without being penalized.

As negotiations continued, the nearly two dozen BNSF and Union Pacific trains that would be canceled Thursday night include: