I was planning on purchasing the Digitrax Super Chief Radio 5 amps but several members in the club told me to buy them Super Chief Radio 8 amp for my HO Layout. They said you will need the power when you start expanding.
Is it ok to use the 8 amp version for my HO layout?
Yes it is fine to use 8 amp Digitrax boosters on your HO layout. The choice between 8 amp and 5 amp command station/boosters, it is a question of how much power your railroad is likely to consume on your railroad as it is built today. If you are planning to expand in the future, it is simple to add more boosters to provide the power and signal requirements of the added track.
Will it burn out my train? I heard several people say the if I use the 8 amp on my HO Layout it will burn my train's engine. If that's true why doesn't my train burn out with the 5 amps.
An 8 amp booster will not burn out your DCC equipped locomotives as long as the decoders are properly installed. If you are running non-DCC equipped locomotives on your railroad with an 8 amp booster, you should not leave them on the track set to 0 speed or you risk melting the shell because of heat build up.
As far as "burning out the train", Digitrax boosters are engineered to detect short circuits and turn track power off to prevent damage to locomotives.
With a larger railroad, using PM42 power managers will be helpful since each one divides the railroad up into four power sub-districts, each of which is protected by its own circuit breaker. When one sub-district experiences an electrical short, the reminder of the railroad remains in operation while the shorted section is shut down for protection.