These are UK-based tour operators and specialist travel agencies featuring rail tours and holidays by train, including vintage and steam trains.

Belmond	020 3117 1300	Classic luxury rail experiences. Belmond operate the Venice Simplon Orient Express train in Europe; The Eastern & Orient Express in SE Asia; The Belmond British Pullman and The Belmond Northern Belle in the UK; The Belmond Grand Hibernian in Ireland; The Royal Scotsman in Scotland; The Belmond Hiram Bingham and The Belmond Andean Explorer in Peru.
Byway	020 4525 6215	Specialise in sustainable ‘no-flight’ travel in Europe, creating travel and accommodation packages using predominately trains, but also bikes, buses and ferries.
Cox & Kings	020 3813 9446	Cox & Kings have a portfolio of around 40 ‘Great Train Journeys of the World’.
Danube Express	0161 928 9410	Central European hotel train, operating since 2008. The train itself offers touring holidays from Istanbul to the Baltic, with itineraries in specific regions and countries eg. Transylvannia or Poland.
Darjeeling Tours	0249 8943	Special interest escorted group railtours to the Darjeeling Himalayan Railway in India since 2002, and SOMETIMES steam railway experiences in New Zealand and Colorado.
Ffestiniog Travel	01766 772030	A spin-off from the Ffestiniog railway enthusiasts. Rail based holidays on scenic routes in thirty countries worldwide. Escorted groups or tailor-made.
Geoff’s Trains & Tours	07752 143657	Small group, hosted (by Geoff) tours in Britain, Europe, Africa and worldwide for tourists and railway enthusiasts.
Golden Eagle Luxury Trains	0161 928 9410	Since 1989 they’ve been well-known to rail tour enthusiasts as GW Travel, specialising in the Trans Siberian Express and exclusive private train journeys to all 15 of the former Soviet Union countries plus China. In 2012 they become bound up with the Golden Eagle – Russia’s first privately-owned, fully en-suite train (hence the name change) operating tours across Russia, Mongolia and China. Now they also operate tours in Europe.
Great Rail Journeys	01904 734 154	Longstanding (30+ yrs) specialist rail tour operator with a large programme of escorted rail holidays to destinations throughout the UK and mainland Europe as well as North America, Russia, India, South Africa and Australasia.
Leger	01709 787 463	Leger have a small programme of holidays by rail around Europe.
Luxury Trains	0333 405 0192	Luxury Trains sell a range of luxury rail tours on, eg. The Blue Train, Venice-Simplon-Orient Express.
PTG Tours	01235 227288	Vintage train tours in Europe (Portugal & Spain in particular) and further afield.
RailBookers	020 3780 2222	Specialise in city breaks by rail, classic rail journeys and train holidays to Europe and beyond. Despite the name, they are not a rail ticketing agency; they create travel packages including accommodation whether that be in hotels or on-board trains.
Rail Discoveries	01904 734 939	Escorted group rail holidays mostly in the UK and Europe, plus a few worldwide itineraries. Sister brand of Great Rail Journeys (above), renamed from Treyn Holidays in Aug 2014.
Railtrail Tours	01538 382323	Longstanding (35+ years) operator offering small escorted holidays by train in the UK & Europe European tours.
Railway Touring Company, The	01553 661 500	Amazing range of specially chartered steam rail journeys in the UK & Europe…..AND in places as diverse as Eritrea, Sri Lanka, China, Peru, Jordan, Syria, Ukraine & Latvia.
Steam Dreams	01483 209888	Operator of The Cathedrals Express, which runs day trips during the summer from London Waterloo on an authentic steam engine, and causes much branding confusion because they also operate steam tours all over the UK and some trips to Europe.
Tailor Made Rail	020 3322 7741	Independent rail travel expert specialising in bespoke rail holidays throughout Europe and around the world.
Train Chartering	01249 890 176	Charter agents who arranges private trains throughout the UK & abroad, and group travel in private carriages on scheduled trains. Their speciality is sourcing, theming and crewing special trains for corporate & private events, film locations & airport or cruise liner transfers. They have two sub-brands, Luxury Train Club offers 26 luxury trains travelling through 35 countries on 4 continents, and they offer private rail car hire on Amtrak trains in the USA through Private Rail Cars.

By the Way – I try to check these for inaccuracies as often as is  reasonable, but it’s always been a fast moving industry. Brands come, brands go, products change. Let me know if there’s something wrong.