Connecting Lionel 1033 transformers together?

[Anonymous]

I am planning to use two separate Lionel 1033 transformers to connect to and power two separate track loops with a connecting section isolated by fiber pins. I remember reading somewhere that there is an advantages to connecting the two 1033 transformers together and using a multiple-transformer approach with one common ground for both track loops. This would be done by connecting the A posts of both transformers together as the common ground. The A post would connect to Clip 2 on the Lockons. Can anyone advise which method is better and why?
Thanks again for this and your earlier answers to my other questions. FTPDream

[lionelsoni]

There is no particular advantage to having a common ground the way you are planning to do it, nor any disadvantage.

However, although it is very commonly done, running a train from a block powered by one transformer to a block powered by another is a little problematical. If the transformer voltages are not closely matched during the transition, a heavy fault current can flow between the transformers, through the wheels and pickups of your train, possibly damaging them. Using two identical transformers as you intend makes it easier to match the voltages and reduces this risk.

I would recommend another approach, however: Connect the outside rails together. Get two single-pole-double-throw (SPDT) switches and connect each switch's common to the center rail of one loop. Connect the other switch terminals to the two transformers. This way, each switch selects which transformer will power the loop that it is associated with. When you want to change loops, just power the new loop from the same transformer as the old loop and run across the gap. Then reassign the old loop to the other transformer if you want to run another train on it.

If you use center-off switches, which are easy to find, you will also have the option of shutting each loop off completely. You may also want to consider subdividing each loop further, with a separate switch for each section, or block. That way, for example, train A already on loop 2 can be stopped while train B crosses from loop 1 to loop 2. Then train B can be stopped while train A crosses to loop 1 on another crossover. With careful selection of the blocks to suit your layout, you can get very flexible operation.