Hey everyone!

Just obtained my first locomotive for the Low Grade Project! I found a nice Penn Central E33 on ebay and jumped on it. At a glance, Bachmann made a nice model of this locomotive, and there were very minor mistakes, along with a nice oil bath when I opened it up. When examining it closer, and reading other testimonials of the model, I would like to do the following:

I'm searching for a water tank car, used on the Gilpin railroad in the late 1800's. I'm finding a lot of round tankers, but this one is a rectangular metal tank on a flatcar. Any ideas, I'm not adverse to hacking the tank together and kit-bashing one onto a flat car myself, but have not found much of any type of tank that would work yet. 

I'm modeling in HOn3 scale so 1/87 sized. The tank held 2200 gallons of water. Basically a metal rectangular tank mounted on top of a narrow gauge flatcar.

I'm curious if anyone has tried retrofitting an athearn BB loco using a standard drop in versus a hard wired unit. 

I'm specifically looking at this: 

http://www.modelrectifier.com/product-p/00111701.htm

But most Decoder manufacturers make similar.

Which will directly drop into many locos such as Athearn Genesis, but It seems to me that such a decoder would also prove an easier fit on a standard BB loco.

I am looking to add a loco to my small railroad. I live in the UK so always have to watch out for import duty and charges plus expensive shipping from the US. Most GP9-GP30 come out at around $170 with DCC and sound.