Layout common issues

A number of Lionel transformers have the sense reversed.  I know the 1033 has the A post as common and the U post to the center rail.  As I recall, many of the single track transformers were that way, the multiple-track ones like the KW and ZW had the U posts as common.

Yep, the LW is a different critter, all right.  But a nice transformer nonetheless.

This is the proper way to connect the LW, The two "A" posts are common, the "U" post is for the center rail, and this does provide the proper polarity for post-1969 whistles and horns.

This is the convention for single throttle Lionel transformers.

Ok, so I reversed the silicone diode and it worked!  I think the fella I bought the diode from was unsure what direction it should be wired in for a modern loco.  Unfortunately I found out the hard way that the old LW had another problem.  It was not making the connection that brought in the resister on the whistle.  As a result, it was putting out a high DC voltage and fried a horn board in one loco.  One bend in a copper slider later it was putting out a nice, even low voltage DC On the whistle button.  So the fried board becomes an opportunity to put in a better horn board.  Oh and I need to buy a circuit tester, since I had to borrow the one I used.

One other question.  The U post does not seem to be making good electrical contact.  I had to search around on the post to get it to read voltage on the meter.   Any ideas on fixing this?

I think I am actually going to use this one for accessory power and get another Z1000 to run the train.  I just feel it'll be safer, plus I'll get the bell button.  The only problem with that is that both my son and I love the LW, but we'll get used to the MTH.

Thanks for for the help everyone!