Hi Ian and Penny. 
When we done a section of the Scottish 500 the other year we were starting from Inverness. We found the simplest way was to fly up from Heathrow. You will have to deflate your tyres, remove pedals and turn your handle bars but was quick and relatively trouble free. We were also required to wrap the tandem which we did with polythene and duct tape. Or you can use a bike bag or transport box but if you are not flying back then polythene may be best as it can be disposed of at the other end. The only issue we had was our gear mech got damaged in transit but we found a great bike shop in Inverness that sorted us out and BA paid for the repair costs when we got back. In hindsight I would probably have made something just to protect the gear mech and chainrings and would do this if we do it again. With BA as we did not have a lot of luggage the bike went free and you can be more sure of departure and arrival times. 
Have a great trip. 
All the best. 
Martin

We've used LNER with a tandem many times from Leeds going south and north.  As you say, the newer Azumas are a tight fit.  You will need to remove both wheels and possibly the rack and rear mudguard.  We just managed to squeeze a full size tandem in one of the bike storage 'cupboards' with rack and mudguard on but we had to ask the guard to unlock the side door to the 'cupboard'.  I can give you a better explanation if you need it.

It's worth checking, but sometimes LNER run Intercity 225 trains and these have the guards carriage into which a tandem can go intact.  You can check what train is scheduled on the LNER website.  When you book bike spaces, they will be in coach P (rather than K for the Azumas).

We now have an S&S tandem which is much easier!

Picture of our previous tandem in an Azuma 'cupboard' attached.

Neil.

Just to add to this, I would strongly recommend going to a local ticket office to book your tickets, it doesn’t have to be in London as long as there’s a manned ticket office - though try and pick a quiet time as you’ll be there for a while. 
We have done this numerous times over the years and our local office have always been super helpful though travelling to and from Birmingham we’ve given up trying to take the tandem, it’s difficult enough trying to get two solo touring bikes into those stupid upright racks, and impossible for my wife if she was travelling on her own! 
Some routes also now state they won’t take tandems- at least last time we tried. 

Anyway, good luck with your trip. We’ve cycled from York to Cambridge and was able to pick up the cycle track out of York which was a nice way to cover some miles - ironically it’s a disused railway! 😎

Hi Ian,

An S&S coupled tandem has been no problem for us on the Azumas.  Just taking the front off makes the tandem shorter than two solos, so if you book two bike spaces, it fits easily (or as easily a two solos).  You just have to be prepared to lift each half to hang on the hooks in the 'cupboard'.  Obviously there's a bit of organisation required to split and get bike and luggage on but if you're travelling from King's Cross to Edinburgh the train probably starts and terminates at these station so it's less of a rush to get on and off.  I tend to undo the cable connectors and loosen the couplings once on the platform so we can disassemble quickly.  A bungee or luggage strap is a good idea to stop the tandem halves swinging around.  I've found the LNER staff quite helpful in general.

Neil.

One thing that might be 'interesting' is the platform you arrive on at Waverley.  Normally trains from Leeds and York arrived and departed from platforms with level access to the ramps up to Waverley Bridge, so getting a tandem out of the station wasn't a problem.  However, there are a few platforms at the Market Street end of the station (and new ones at Waverley Steps end) that would need use of steps or a lift to get to the ramps or out of the station.  The last time I got a train to and from Edinburgh in May (without bike) the trains arrived and departed from one of these.

The problem ones would be 1, 8, 9, 10 and 20 on the following plan: Edinburgh_station_map.jpg (1500×2667) (nationalrail.co.uk).  The LNER trains always used to arrive and depart from 2 or 19 on this plan.

Someone in Edinburgh might have more information.

Neil.

Thanks everyone. We are going to go with Roberts advice and will book an Avanti train. I have just had an online chat and they have confirmed they will take a tandem. 

I will worry about getting off the platform when we get there, but by then I will be in holiday mode and everything will be fine!

Penny

p.s. Andy, was it you we bought the tent from? its going on its first trip with us 

It most definitely was. Hope you have good weather for your trip. 

If you get stuck somewhere, let us know, we still have the tandem roof rack. 👍🏻😎👍🏻

Andy,

Even more ironically, that old railway line that you used at the start of York to Cambridge was the old East Coast Mainline, which was diverted when the Selby Superpit coal mine opened in the early 80s. Incidentally, it has recently been widened and resurfaced to remove tree roots. 

Definitely a thumbs up for the Avanti pendelino, we just wheeled on and left it with all rear luggage in situ for the journey. Double thumbs up for Richard the train driver who got the train 're-platformed' in Edinburgh so we could wheel out the same side without splitting the bike (he left a note in our luggage to let us know - photo hopefully attached). At Edinburgh we did find lifts big enough for a complete tandem after a bit of wandering. 

Unfortunately we finished our trip a bit early due to storms across the UK but got home with EMR OK. I will be slightly more relaxed about travelling by train with camping luggage in future!

Penny