'''96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '12 Surly Pacer, All are 3x8,9 or 10. It is hilly around here!
I had an '83 400 set up as my rain bike and it was a great frame but a broken Simplex derailleur isn't much of a surprise.
Assuming you have friction front shifting (downtube or bar end shifters) you can use nearly ANY road front derailleur with the proper clamp diameter or get a braze-on model with a 28.6 mm adapter clamp. Road front derailleurs are universally bottom pull and friction shifting lets you trim anything to run smoothly.
I'm currently running a Shimano 105 10-speed front derailleur on a bike with an 8-speed cassette and a 7/8-speed chain. Since it has friction shifters it works wonderfully.