Sorry for posting in English ...
For a large loco, you may be better off with a main line steam special (assuming it's not too expensive for you - mostly more than 100 pounds although there are some cheaper).
http://uksteam.info lists all the main line steam workings that are planned. There's a page for 2016 and another for 2017.
For each tour, it gives the date, a short description with details of the expected locomotive and what part of the tour the steam loco should work (mainline steam tours often have a diesel loco at the start and the end of the tour). There's also a link to the operator from which you would be able to book if it's not full.
All main line steam locos will at least be a 4-6-0 in UK terms but there are also Pacifics in the list. Atlantics and Mikados were very rare in the UK.
Sorry voor het gebruik van Google Translate of deepl.com om van het Engels naar het Nederlands te vertalen.
Sorry for using Google Translate or deepl.com to translate from English to Dutch.