I am an airline pricing strategy specialist (
check out my site!) and travel by rail in the UK quite a bit, so I might be qualified to comment based on what I have observed out there in the market. I will comment specifically on Advances, mainly for VTEC since they are my regular operator.
VTEC
(i)
Fare range: Offer a wide range of fares, ranging from cheap to extremely expensive, across both compartments - Advance fares available in almost all markets
(ii)
Non-dynamic discounting: In light of (i) there is no need to have frequent sales and promotions, save one or two regulars through the year
(iii)
Dynamic discounting and incrementing: Not practiced
(iv)
Inflation: Fares increase a small amount every year, sometimes approximately every six months
(v)
Fare mix: Set inventory levels when trains become available and (by appearances) do not actively manage the availability so when fares sell out they sell out, even if forecasts change significantly - all fares appear to be used extensively
(vi)
Construction logic: O&D based
(vii)
Optimisation logic: leg & segment based
(viii)
Overbooking: STD to 1ST upsell on trains that are forecast to be busy in STD but not in 1ST is unlikely to be high, managing overbooking through encouraging passengers who might otherwise sell STD to voluntarily upgrade (Seat Frog role unknown); actively set high prices on services forecast to be busy and set low prices on services forecast not to be busy, even when close in the schedule
(ix)
Ancillaries: Fully bundled service in 1ST, limited bundling available in STD - catering is high quality and appears to offer passengers things that they actually want, for a price - I do not know whether or not the catering prices are set by the pricing department or someone else
(x)
Corporate deals: I don't know anything about this
(xi)
Schedule element: Trains with fewer stops are almost always more expensive, even at times of day when both few-stop and many-stop services are forecast with low demand
GWR & CrossCountry
1ST fares seem extremely expensive and frequently the lower range of the fares that are filed appear to have extremely limited availability, even early in the booking window when (i) high willingness to pay travellers are not booking and (ii) when STD is forecast to be busy yet 1ST departs nearly empty
Hope that helps!