You may want to get a cheaper beginner's camera but I personally think that you should go a bit further and invest for the future.
Firstly, CCD sensors are better than CMOS sensors and although they are a little more costly, you should go a CCD sonsor.
Megapixels is the measure of resolution that reflects the ability of a digital camera to record detail. The higher the resolution the more detailed the picture is. Although many cameras can record up to 10 megapixels, I find that even a 2 megapixels images is quite detailed.
Almost every digital camera has zoom feature, but watch for for digital zoom. Digital zoom, simply enlarges the picture using the CPU and this can result in a blurry picture. You should go for a camera that has optical zoom as well as digital zoom. Unlike digital zoom, optical zoom, keeps the image sharp whilst the object is zoomed in.
Next thing to consider is the weight and size of the camera. If you want to have a light camera, you may want to choose cameras that uses a unique rechargeable battery, these batteries are often smaller and lighter then traditional AA batteries.
If you want to photograph high speed trains (Not nessasarily HST's) you may also want a built-in sports mode setting for capturing high speed motions. This reduces the motion blur as it uses a higher shutter speed.
By all means, look around and see which one you like and ask if in doubt.
I'd certainly agree that CMOS is inferior at the low end, but you'll find a CMOS sensor in most DSLRs (you don't want an SLR type camera the first time around, not that your budget would stretch). This has a lot to do with the requirement for high speed operation.
The number of megapixels has three effects. Firstly how large you can make the image before the pixels can be seen by the eye, which causes a blurring effect. This may be hardly relevant at all if you don't intend to print things. Secondly how much you can use a digital zoom before the first point causes problems. You should generally avoid using digital zoom at all on cameras. Your computer can do a better job. Thirdly more pixels means a larger image file size, but this is becoming less relevant with the lower and lower price of memory.
If you can get a camera with an extra screen behind a viewfinder you'll find it much easier to use outdoors as LCD screens can be difficult to see in bright light. My first camera was almost point and pray in bright light as I had to use the main screen, which was impossible to see.