Train passengers in Lincolnshire, parts of Yorkshire and Cambridgeshire have been warned of delays on Saturday because of East Coast mainline works.
People who use level crossings are being warned of the delays from 1100 BST to midnight on 9 and 16 October.
A total of 56 extra trains will travel through the diversion area, which includes Lincoln city centre.
Network Rail apologised but said but signallers will try to keep the disruption to a minimum.
Some trains are being diverted from Peterborough via Spalding and Lincoln to Newark, whilst others will continue along the line from Lincoln via Gainsborough and on to Doncaster.
The works are being completed at the weekend as there are fewer trains running on the East Coast mainline than on weekdays, Network Rail said.
Network Rail's Kevin Preece said: "These works are an essential investment to maintain the quality of the track on east coast and prevent us from having to impose a speed restriction which would disrupt many more passengers.
"The level crossings in Lincolnshire are used by many hundreds of people and I apologise for the disruption this will cause to them."