Apart from price which one whould be better for qualty and sound? rambo1...
The Rapido one is "state of the art", a fairly new model. The Walthers one isn't bad, but it's older and not as precisely detailed. If you can afford Rapido, it's your best bet between these two.
If you're into GM cars, the Rapido is a Cadillac, the Walthers a Chevy. Both are good, but one is better (and more expensive).
rambo1 Apart from price which one whould be better for qualty and sound? rambo1...
Is there any question? Rapido's is the total Cat's meow - it's like better than Athearn Genesis. No contest.
If you had to rate them on a scale of 1 to 10, the Rapido would be a 10, and the Walthers Trainline F40PH would maybe a 6.5 - it was pretty decent when it came out but the paint job was medocre. With the newer version, it may be improved to a 7 or a little better - will have to wait and see. The price will be a good deal higher and not sure if it will place it at or better than the KATO for the similar price.
If Athearn Genesis made an F40PH, it would be a 9 but no such beast exists; KATO's is maybe an 8 - it looks pretty good but has some minor faults including the nose and the pilot.
I own three KATO's and three Walthers Trainline F40PH's btw.
The Trainline F40PH's were about the best thing I could find back then that was non brass when they came out because all that was on the market was brass, Bachmann Spectrum and Walthers Trainline. The Bachmann Spectrum had some pretty serious faults so I sold those two I had and purchased immediately the Walthers F40PH's as soon as they hit the marketas they were quite decent and a major improvement over the Spectrum F40PH, despite being a "budget" F40PH. KATO followed on a few years later with theirs which I also bought when they first came out.
The Rapdio are absolutely gorgeous! I've seen the Canadian version in person and it's awesome - accurate, very detailed - state of the art - the last word in F40PH - FINALLY! The Amtrak phase I version is due out this fall, and hopefully they will follow on with a phase II version.
Rio Grande. The Action Road - Focus 1977-1983
I have to agree with what's already been said here. The Rapido is in a whole other class from the Walthers loco, in every respect. The detailing on the Rapido units is stunning, they're incredibly accurate, and they run extremely well (I say, based on my experiences with the VIA version).
The Walthers are decent locomotives and run well, but they lack much of anything by way of detail. There's also differences if you want to get into specific versions: for the VIA units, for example, the Rapido is 100% correct, while the Walthers is an Amtrak unit painted in VIA colours. For Amtrak, the Rapido and Walthers represent difference body phases for the loco (the upcoming Rapido model is a Phase 1 F40PH, while the Walthers is a different phase....can't recall which one).
Now as for sound: There is only one choice here, and I'll explain why. The Rapido unit comes with a Loksound decoder, while the WalthersMainline comes with a stripped-down Soundtraxx decoder. Both replicate an EMD 645 prime mover, but only the Loksound is a true F40PH. The key issue is with the Head-End Power (HEP). F40's were colloquially known as "screamers", because in order to provide HEP to the train, the engine had to run in notch 8 all the time. Loksound replicates this really nicely. When you start up the loco, it's in normal "freight" mode. It can run and will proceed through the notches normally, but it can't power a passenger train. Pressing one button (F4) will put it into Standby mode, where it revs up to notch 6 to provide power when idling in a station. Then press F5, and the unit goes into full Run mode.
This makes the operation extremely prototypical, and also makes the units sound like a proper F40PH should. The Soundtraxx decoder doesn't have this function, so to simulate it you'd have to turn on manual notching and turn the prime mover up to Run 8 yourself. This is much less convenient, and also doesn't have the proper sound, as you'll end up more slowly going up or down through the notches. I'm also not sure if this function is available on the stripped-down Soundtraxx decoder in the Walthers units.
Add to that the fact that the Loksound has all-around great sounds, brilliant horns, amazing slow-speed operation and lots of other neat functions (particularly the Rapido units....they've been rigged up with some other special functions), and it's a hands-down win for the Rapido/Loksound.
The Rapido units will also have full prototypical lighting effects (including lit numberboards, marker lights, strobes, and even step lights), while the Walthers only has forward and reverse headlights.
So in all ways it's a huge win for Rapido. However, if you're looking for a more economical budget model, the Walthers unit is a decent buy. It's also available in more paint schemes (Rapido may well do more, just give it time), and it's a good base for a superdetailing or kitbashing project. But if you can save up the $$ for the Rapido (easier than you may think, if you put a little aside at a time in the lead-up to the release), it will be worth every penny.
-Tim