Originally Posted by: NZMarklinist 
Probably the correct answer is NO they are not reliable enough!!
They maybe OK for analogue use if you can be sure the high voltage cables are in good condition, but don't put them anywhere near anything Digital !!
Just saying that is all
Thanks for comments gentlemen,
I have used my blue 30VA with two digital loks and they worked beautifully.
I was surprised how they also reversed seamlessly when in analog mode as they interpret the reversing high-voltage in the decoder and reverse as they should, without the jumping that the poorly adjusted tension spring in analog loks lend themselves to.
Other than the high-voltage in reverse, I don't understand how they can be too high voltage when my 6002 is 52VA.
Is it a question of how the voltage is applied? Can anyone with electrical knowledge explain that?
I have not yet tried using my 6002, nor the 6021 compliment, which is sitting here in styro box besides me.
I also wanted to know is if the blue transformers would work to add power to a large layout in series with digital,
as long as they were "locked-down" in a fixed high-speed position, thus applying adequate VA to compliment.
If not the blue ones, what about the newer white ones? I will need notes on polarizing too. I saw something the EE had in their literature about polarizing the current, but will have to check again.
I do appreciate your comments about the insulator and would like to know if I got an electrician to take a good look at them, that they may be useful. I have 7 of these, three are 30VA-6115 and the old "Marklin Super" 280, one is 16VA-6507 (immaculate condition), and three some are much newer 10VA (I am not sure about the correct numbers but one says 37547, another 37549, these two of have dials in mediocre condition).
However, if that is too much work and too risky, I might consider investing in newer transformers, but I will see what I can do to use my blue meanies safely with analog equipment. Tom, I do see how the rapid short-circuit switch off in the 6647 is a great advantage.
Brandon can drive his firetruck when he comes to visit, and bring up the hose and extinguisher so at least he will be safe.
- Mark