Technical

I see a lot of reference to A3 and A4 engines can someone tell what engines are what and the differences between them?

Also I have just bought a Mallard Starter set and noticed that it has come with 7 straight sections of track and a half length power track (which the plastic cover over the conector has obviously been very hot as it has distorted) would the set have had another half length of track to make a proper oval? obvious answer is yes.. I intend to purchase some 4th radius bends and other track as I have read in several place thats what is better to run LS on?

thanks in advance