If you don't feel like spending many hours in a train, you can consider travelling by plane. Especially if you have the possibility to book in advance, flying to Omsk can be definitely cheap.
What are the departure and arrival stations in Chertkovo and Omsk?
You can take the train to Omsk at ЧЕРТКОВО, which arrives at ОМСК-ПАССАЖИРСКИЙ.
When are the first and last trains from Chertkovo to Omsk scheduled?
It will take you 5 hours and 47 minutes to reach Omsk. The earliest train leaves Chertkovo at 11:11, whereas the last one leaves at 11:11.