You definitely need a good height adjustment method and there have been pictures and information on here and in ME I think over the years. Some involve a trolley jack but if using hydraulic I would advise an additional mechanical ratchet system ‘just in case’. Nowadays a screw thread system can be powered by your battery drill.
I started with a Dexion trolley 2ft high only a bit bigger than the loco (0-6-0). Fine when standing but even moving across the typical garage concrete on little wheels was worrying. Same wheels when trolley rebuilt 6in high is fine. beware castors moving the support position. I use a 30in x 18in hydraulic table to lift it at the car boot.

Steve, there are various things to consider, depending on the environment. The following is what works for me – not necessarily for anyone else.
I started with a bought-in hydraulic jobby and extended it with thick marine ply. This gives me a good range in height and enough room to work around the engine. I fitted rails which are removable. I find rails are mostly restrictive and a nuisance. They are a must for some model engineers but the flexibility I get without them is amazing.
The extension (not in use most of the time) allows me to get up and under if I need to for quick jobs like grates. It also allows me to steam up a Britannia at home with the tender in situ.
Something else to consider is the car. An estate car with a lip is a pain – as is one in which the rear seats do not go flat. There are cars with flat rear entry and flat rear seats. I find it best to have fittings in the car to secure the box and put the loco in the box.
Like I say, it works for me – not necessarily for anyone else. I am hoping you can see the picture – if not I’m working on it!

https://www.tonykendall.co.uk/Trolley%20(2).jpg

I use a 4 wheel garden trolley, adapted to have drop down lockable feet at the rear.  To offload onto the ground level track, I wheel the trolley over the track, drop the feet and then fix a ramp between the trolley and the track.

For loading into the car (Toyota RAV4), I have a length of sliding door track that I attach to the roof bars which extends beyond the rear of the car and have a sliding block and tackle which I attach to the skeletal loco transport “Box”.  Lift that from the trolley into the car.

The sliding door track remains on the car with a bright red safety plug on its outboard end.

My 5″ loco is an LBSC Speed tank loco about 35Kg weight.

Bob

I suspect the Tony Kendal link is one of these https://www.machinemart.co.uk/p/htl500-500kg-hydraulic-lifting-table/ not cheap at over £500. Cheaper models are available

Yes, you are right Duncan. Prices for this have doubled since I bought it 20 years ago.
I needed the lifting capacity for another job so the choice was small.
Unless you go for a double scissor, the trucks that go lower do not go high enough for me and vice-versa. It’s surprising how the lowest height comes in handy. Most of the ones that go low don’t go to bench height which is important for me. Often the advertisers do not understand we need this information.
None had a big enough surface for what I wanted, so I extended it in the simplest way.
For me it is in my top 3 workshop essentials and gets used for all sorts of things – particularly as I get older and lifting is something which I have to consider for longer!
Apologies to Steve for taking so long to reply.