Not only does the Czech national rail operator CD, provide multiple different services on the Prague to Oloumuc route, it also has competition from both RegioJet and Leo Express services.
If you want to compare all the services, in terms of the prices and the departure times, the best method is to look up the journey on each operator's respective website.
The Czech version of the Trainline webite features the trains of all three operators, plus buses, but it doesn't seemingly offer the cheapest prices for CD's trains.
Though the prices on CD will be in Czeck korunas (CZKs), but the prices on Regiojet and Leo Express are displayed in €s.
Book early and save: Yes*
Online bookings open: Up to 8 weeks ahead (CD); 4 weeks ahead (RegioJet), 6 months ahead (Leo Express)
Note that you can compare the prices of all three operators from around 4 weeks ahead, when the tickets for the RegioJet trains are placed on sale.
If you look up this journey 4 weeks ahead, then it's highly likely that the cheapest* tickets for the CD and LeoExpress trains will still be available - this is not a route on which you need to book more than a month ahead to make savings.
*This is also a route on which the national rail operator CD, České dráhy, offers limited numbers of ‘Special Offer’ tickets, also known as ‘Akcni jizdenka’ tickets.
Though 2nd/standard/economy class tickets prices tend to vary across the operators by less than the equivalent of €5 - AND you will also typically save less than €5 by booking 2nd/standard/economy class tickets in advance online.
Our general guide to Czech train tickets is available here - and we have also published a guide to booking tickets on the CD website.
Seat Reservations:
Seats will be assigned if you book tickets to travel on CD's Supercity trains, though you can opt to choose specific seats on a seating plan.
On the Ex, EC, IC and Regional services operated by CD, you can opt to add a complimentary seat reservation when booking, or if you opt to subsequently add a reservation to an existing booking you can pay a 75 CZK fee.
When making these reservations you can choose to use the seating plan - which also indicates which seats are forward facing.
When booking tickets on the RegioJet and Leo Express trains, you select a specific seat (s) from a seating plan that is part of the booking path - there is no charge for having these assigned/reserved seats.
On the Leo Express booking path, you can see which seats are forward facing.
Comparing the on board experiences:
The CD, Leo Express and RegioJet websites go the extra mile to inform prospective ticket purchasers, of the on-board facilities that will both be available on each specific departure AND the additional benefits of booking the respective classes of service.
It's worth paying attention to this information, booking a 2nd class ticket for a journey by a CD train, particularly a SuperCity or EC service, will provide a different travel experience to, for example, travelling in Low Cost class on a RegioJet train.
Note that Leo Express and RegioJet don't brand their tickets as 1st or 2nd class.