Switching python app from sqlite to postgres

I have been looking at an application I downloaded from Sourceforge for
model railroading[1]. So far it has two strikes against it. It uses
Python 3, and it uses sqlite-3. Other than that, it looks like it might
be a useful program.

I tried to build and run the software, but Slackware uses and bundles
Python 2 and although I also have 3.1 installed, the packaged
installation of the sqlite-3 drivers only runs with version 2. Py 3
still says they're not installed.

So the next step is likely to switch the code to use Postgres. The
database interface is limited to three Python source files, so I don't
think it will be too difficult, if I can find some guidelines on how to
do it. Does anyone know where I might find some information on how to
make this conversion?

Thank you,

Bob McConnell
N2SPP

[1]  Model Operations Processing System