A third union -- the last of 13 unions without a deal -- said it would extend the deadline for an agreement by two months.
The breakthrough followed proposals in Congress earlier in the day aimed at supporting White House efforts to avoid a major transportation disruption at the height of the holiday shipping season. The work stoppage involving close to 50,000 workers could have begun as early as next week.
"Everyone wins when we reach voluntary agreements," said A. Kenneth Gradia, chairman of the negotiating group that represented carriers including CSX Corp , Norfolk Southern , Union Pacific and Burlington Northern Santa Fe, owned by Warren Buffett's Berkshire Hathaway Inc .
With the agreements on Thursday night, 12 of 13 unions representing 130,000 railroad employees have struck deals in two years of bargaining.
A presidential board appointed in October to help the parties overcome impasse played a key role in facilitating the most recent agreements.
Unions settling on Thursday included locomotive engineers and dispatchers. Maintenance workers agreed to extend their talks until Feb. 8.
The parties had been facing a Dec. 6 timeframe for reaching settlements. A strike had been considered unlikely, but was not out of the question. A freight rail strike could have disrupted certain Amtrak passenger and commuter services even though those railroads were not involved in bargaining.
Government intervention is permitted under federal law in railroad and airline disputes if an impasse or potential strike is considered damaging to commerce.
Increased healthcare costs were a sticking point in talks. (Reuters)
