How to set up a second MTH train on my layout

It would help to let us know if the locomotive and starter set are recently made and have PS3 as the operating system (or earlier, PS2).  Most of us don't have the time or energy to look up the specific number, but you have the packaging that describes them in detail.  If they are both command control (PS3 or PS2) as I suspect, you're set to operate them in DCS command mode.  You need some sort of DCS system to operate both in command mode.  The DCS Remote Commander is able to control one loco at a time, essentially conventional mode although allowing access to command functions of PS3 and PS2.

Options for command control of PS2 and PS3 locos include purchasing a DCS system (consists of a TIU and a hand held remote or a TIU/WIU that uses an app on your smart phone or tablet) or purchasing the MTH Explorer (a more limited and much less expensive way to to access command control through DCS).  Figure $300 to 400 for the TIU or TIU/WIU and $120 or so for the Explorer.  You'll also need a power supply for the Explorer, but you may be able to use the power supply that came with your set.

If you are happy to operate them independently on two electrically separate loops of track, you can use the Remote Commander for one and another MTH transformer (e.g., Z-1000) to control two separate trains in conventional mode, but many of the command functions will not be accessible.

The DCS Remote Commander will run your new engine, but the locomotive must be set to the factory default engine identification number (01). You can also run both locomotives at the same time with the Remote Commander, but they will both do exactly the same thing.  In other words, if you press a button on the remote then both locomotives will respond at the same time. You can't enter commands for a specific locomotive.

If you want individual control of 2 or more DCS locomotives, then you need a TIU and the hand held DCS remote.  (You also have the option to use the WIU and a phone/tablet instead of the DCS remote). The TIU is more complicated and more expensive than the Remote Commander system. Before purchasing one, I would recommend reading "The DCS Companion, 3rd edition" by Barry Broskowitz.  It is full of useful information, and it will also give you an idea of what you're getting into.

The DCS Explorer is another option that will control up to 3 locomotives but with limited functions. I have never used it, so I can't give you an opinion about how well it functions.

Glenn,

It's looks like the engines you have are both PS3. As John stated, you can run either engine on a track with your DCS Remote commander or both at the same time  on the same track and they will both do the same thing when commanded.  All engines come from the factory set to DCS ID 01, if they have ever been changed, they can be reset back to the original ID by performing a factory reset with the DCS Remote commander:

• Press the following buttons in the order listed below (remember - you are pointing the remote at the IR base, not the engine)
  • SND
  • DIR
  • - (this the minus symbol indicated when you press on the bottom half of the center, gray rocker)
• You will get a two toot response from the engine and it will now be alive with lights, sound smoke, etc

If you have two tracks you can run both engines on individual tracks with one DCS Remote commander remote but you will need to purchase an additional DCS remote commander receiver.  My son built a carpet layout years ago with four individual tracks and trains, put a DCS Remote commander receiver on each track and ran them all individually with one DCS Remote commander remote by simply point the remote to the receiver of the track & train he wanted to control. It worked really well, just make sure to not place the receivers to close together.

If you have a conventional transformer you can control most of the command features with the bell and Whistle buttons. See the excerpt from the MTH manual below:

These procedures also work on all PS3 engines. The only command function not available is the Volume Control which can still be adjusted from the POT adjustment screw on the bottom of tender or engine.