Train seat reservations sold out three weeks ahead, what are my real options Transport

Before anything else, check the operator's own website rather than the reseller you have been using. Third party sites frequently see only part of the inventory, and reseller sold out very often means available on the national operator's site at the same price.

After that, in rough order of how often they work for me:

• split the journey, book A to B and B to C separately, which uses different quotas and often finds seats when the through booking will not
• look at the slower regional trains, which usually do not require a reservation at all and cost less
• check departures from a nearby station on the same line, one stop earlier is often wide open
• check back 48 hours before, when unpaid holds and business bookings get released
• night train if the route has one, which also saves a hotel night

Also look at first class before you write it off. On busy routes the cheap second class buckets go first, and first can end up only 15 to 20 percent more expensive than the last remaining second class seat, sometimes less. Worth ten seconds of checking.

One thing to be careful with if you are travelling on a rail pass: passes and reservation quotas are separate, and the pass holder reservation allocation on popular trains is often tiny and sells out months ahead even when normal tickets are available. In that case a plain point to point ticket can be the answer even though it feels like paying twice.

If none of that works, long distance coaches on major intercity routes are usually bookable much later, cost less, and take maybe 60 to 90 percent longer. Not glamorous, but it keeps your fixed hotel date intact and you can sleep on it.