A very basic way would be to use a spreadsheet program like Microsoft Excel to arrange the information in the form of a table.
Make column headings across the top for all the information you want to track for each car (e.g. "Road #", "Coupler Type", etc).
At least one of the columns should be for something that is *unique* for each car, such as "Car Number". It's probably easiest to make this the very first column.
Then, fill in all the information. Each row will contain the information for one car - it will be the "record" for that car.
After you've typed in all the info for each car, you can sort it. In Excel, these data sorting commands are under the "Data" menu (e.g. Data -> Sort).
For example, if you want to look up a car by its number, sort the rows (records) based on the "Car Number" column. Then you can easily find the car number you're looking for, with all its information. You could print that row, or the whole table.
You can sort by any of the columns. If you want to see all the cars for a certain Road #, sort on that column, and all the car records will be grouped by Road #.
Guess what, you've just created a very basic "database".
You don't have to use Excel, many programs let you create tables and sort them, but Excel is so common, and it's pretty easy to do something basic like this.
If you get into it, you can create forms, reports, and so on. But if you just want to track some basic information in a convenient way, a simple table like this is probably all you need.
Hope this helps. Good luck!
