One of the problems of software in our hobby including inventory, track planning, signaling, etc. is that many of these products are the work of a single person. As long as that person stays involved these products grow and improve with time and are supported. Sometimes that person gets sick or has change in life's circumstances and s/he turns away from the software and it ceases to evolve and support becomes minimum and declines over time. Thus a program that requires Windoz XP. The size of the market makes it tough for professional software company to have a team on it.
The idea of having an inventory program with a database of all trains would be an enormous project requiring constant updating. Think of the scope of the Greenberg books. Very cool feature to have.
Excel is not a relational database, but one can still do a lot with it. A lot is in how it is set up. Many people (including me at first) have a tab for engines, one for cars, etc. This limits reporting. Excel has a number of intrinsic database functions, such as "filter and sort", "Find Duplicates", etc. These are designed for the master data to be in a single sheet. Some codes are needed to allow for sorting and reporting. Thus, if one creates a column such as "Type" with values of "Engine", "Coach", "Accessory", etc. the database functions of Excel can do some reporting. A column with color would allow one to answer a question such as "How many engines and coaches do I have that are red?" One would have to do some studying of these database functions to make good use of them. Its clunky dealing with pictures, but possible.