There numerous issues with running Trainz on a $1000 laptop. These issues range from slow 5400 rpm and less hard drives, to slower processor speeds due to thermal cooling and power settings, right down to the video chipset.
You have to remember that a laptop is not really meant to run high-end applications like a desktop due to the reasons mentioned above. They are for remote light use even though the specs of laptops is encroaching upon desktops in many areas.
If are interested in a laptop for Trainz, check out the more substantial Alienware machines, which use discrete video and sound as well as real processors. The price is also more substantial too like 3 times what you paid for your current machine.
I have an Alienware M17x that I got last March. This machine handles both TRS2010 and TS12 just as my desktop does. It comes with 8GB of RAM, the ATI6850 video card and a decent sound system. There are also two 640GB drives RAID'd together to give me 1.2TB of space. These drives too are not the normal 4500 or 5400 RPM laptop drives. Instead they are 7200 RPM Seagates, which really are fast.
John