Diference between PS2 & PS3

Most importantly; no battery in PS3!

Sounds at least in some engines are better for PS3 than their ps2 counter parts, example is the latest big boy.  

You get the wonderful "wireless" tether, some like it, some don't.

Do a search, there are plenty of differences.  G

The following from The DCS Companion 3rd Edition, pages 15-16, may help:

Differences Between PS2 and PS3 Engines 

Although all PS2 and PS3 engines are DCS engines and can be operated on a mix-and-match basis with each other under DCS (or even conventionally), the two types of engines are different in several ways. 

PS2 engines were first available from MTH starting in the year 2000, and PS3 engines were an evolution of the PS2 design that followed several years later. As a result of that evolution, there are several important differences between PS2 and PS3 engines. 

PS3 engines contain a PS3 board, rather than a PS2 board. This technologically more advanced board, in addition to being smaller and requiring less power than a PS2 board, provides a number of differences between PS2 and PS3 engines: 

• The most important difference between PS2 and PS3 engines is the type of computer chip used as a Digital Signal Processor (DSP). The DSP is the sender and receiver of DCS data packet commands, and the nature of the computer chip that is used to send and receive these commands has a direct effect on DCS signal strength. PS2 engines use an Application Specific Integrated Circuit (ASIC) chip, while PS3 engines use a much faster Field Programmable Gate Array (FPGA) chip. The nature of the FPGA allows PS3 engines to, “listen better”, for DCS commands, allowing for much improved DCS signal strength. 
• One feature of the PS3 board is that in addition to PS3 engines being capable of operating under DCS or conventionally, just as are MTH's PS2 engines, they also contain an on-board Digital Command Control (DCC) receiver that allows them to be controlled by DCC, a very popular command control system. This capability allows a DCC operator to purchase a PS3 engine for initially on a DCC layout and then add DCS capability at a later date. 
• Under DCC, PS3 engines have the ability to execute 29 (0-28) different DCS functions from a DCC controller's function keys. Although at present there are few, if any, DCC controllers available that actually have 29 different function keys, when such controllers become available MTH PS3 engines will immediately be able to utilize the additional function keys. For a detailed explanation of how to operate a PS3 engine under DCC, or conventional, control, refer to the instruction manual that accompanied the particular PS3 engine. 
• Another feature of the PS3 board is that PS3 engines do not require a battery for operation, regardless of whether they are being operated under DCS or DCC, or conventionally. Where PS2 engines are dependent upon a battery to retain changed settings on the PS2 board, including their actual DCS ID#, PS3 engines are not. They use a “super capacitor" type of device instead of a battery. This eliminates many of the most common problems encountered by DCS operators that are caused by a weak or dead battery within a PS2 engine. 
• Newer O gauge PS2 engines are available with a 2 rail/3 rail switch, accessible from the outside of the engine, that allows the DCS operator to select whether the PS2 engine is to be run on 2 rail or 3 rail track. However, when operating such a PS2 engine on 2-rail track, the DCS operator must ensure that the engine is properly oriented, such that it knows which of the two rails carries the DCS commands from the TIU, DCS Remote Commander or DCS Commander, and which rail carries the acknowledgement signal back from the PS2 engine. PS3 engines, however, are able to sense which rail carries the DCS signal and which rail carries the acknowledgement from the engine, and can automatically adjust the engine's electronics for proper DCS operation. 
• Revised firmware allows newer PS3 engines to be started up in DCS mode by simply rolling the thumbwheel up 1 click to 1 SMPH or via the Quickset Speed Command. This will also cause the engine to move forward.
• Revised firmware allows newer PS3 engines, manufactured starting in 2014, to have the capability to be reset to factory default settings through a combination of button presses using the DCS Remote Commander (SND, DIR, -). The engine will issue a double horn/whistle sound and start up under DCS. 
• Revised firmware allows newer PS3 engines, while operating in conventional mode, to turn marker lights on and off with one Whistle button press, followed by one Bell button press. 
• PS3 steam engines adhere to prototypical Rule 17 lighting, while PS2 steam engines do not. This means that when a PS3 steam engine is in neutral or its direction is reversed, the engine's rear headlight, if present, will illuminate. However, instead of the front headlight turning off, it will, instead, become dim as per Rule 17. 
• All PS2 engines with ditch lights have the capability to flash their ditch lights whenever the engine is moving forward or sitting still and ready to move forward, and the engine's horn is activated by pressing the W/H key on the DCS Remote, DCS Remote Commander handheld control or the DCS Commander. PS3 engines, however, must be moving in order to flash the ditch lights when the horn is sounded. Further, a PS3 engine may have functional rear ditch lights, as well as front ditch lights. 
• A PS2 engine with an interior light will, when that light is turned on, have that light on all of the time. A PS3 engine’s interior light is only on when the engine is stopped. 
• If a PS2 engine’s direction is reversed while the engine is moving and the thumbwheel (or the Quickset Speed function) is then used to increase the engine’s speed from zero, the PS2 engine will slow to match the set speed and continue in the same direction. However, if the same operations are performed with a PS3 engine, the engine will, instead, slow to a halt, reverse direction and speed up to match the set speed.

This and a whole lot more is all in “The DCS Companion 3rd Edition!" This book is available from many fine OGR advertisers and forum sponsors, or as an eBook or a printed book at OGR’s web store!

Nice comprehensive list of the differences.

Thanks so much you guys, I will pass this on to the Person who asked me!!!

Thanks again,

Fred