Just a few comments to add to the previous replies here, in no particular order
The 1000D is the 'entry level' DSLR from Canon, but it is still capable of extremely good results. The biggest influence on the quality of the images it can produce is the the lens on the front, and the person behind it
The 18-55 IS 'kit' lens is pretty good for the money (far, far better than the previous non-IS version which basically was/is cr*p IMO) for starting out I don't think you will get better value/quality.
For railway photography you will probably need something 'longer' than the 18-55 type range, but this depends on your style of shooting and locations etc.
Spending more money in this area will pay dividends but to start with I'd opt for the 18-55 IS (make sure it is the IS version as I said earlier, the old non-IS is not woth having IMO)
IS (Image Stabilisation) is pretty much useless for any moving object (a train for instance!) but can be useful to help steady a shot of something stationary.
The maximum aperture of the lens will be dictated by the amount of money you spend. If you want fast f/2.8 zooms then they will cost big money, but for most things in good light the f/5.6 ish of most 'consumer' zooms is ok.
Memory cards - Good advice is to have at least two - as mentioned if one fails (I've never had one fail...so far!) you have another, but memory cards are relatively cheap these days so get a card that will hold a few hundred shots minimum (at least 4Gb).
RAW - Certainly worth shooting in RAW, if only to be able to change the White Balance accurately after taking the shot. This can be a PITA to sort out from a jpeg. Most of the time the cameras auto white balance will be ok but like most auto functions it can have a mind of its own sometimes
You can of course set the WB manually but the presets don't always match the actual light.
You also have more room for correcting the exposure in post processing, but not a recommended method of shooting, try to get it right 'in-camera'.
The RAW file is actually the raw data that the sensor sends to the camera processing circuitry that produces a jpeg if you have the camera set to jpeg shooting.
This will apply the in-camera settings relating to contrast, colour saturation, sharpness, picture style etc. etc. When you process the RAW file you have the option to apply these how you want after shooting. i.e you decide how the image looks not the camera.
To start with I'd shoot jpeg to get used to the camera but I'd seriously consider using RAW asap to give you more options later.
Software - The Canon comes with DPP (Digital Photo Professional), this will process/convert the RAW files and quite a powerful piece of software. You can also use Photoshop, Photoshop Elements, Adobe Lightroom or a few other programs to convert.
The best thing is to have a play...
Hope this is of help to you and (sort of) makes sense!
)
Thought I was on either 800 or 400, that'll teach me to check 1st!