The following bookmarklet can be used to create Vega-Lite graphs of the player value for 18xx.Games games.
Don't click this, bookmark it: copy 18xx graph
Simply bookmark the link above (right click, then bookmark link), head to the spreadsheet tab of an 18xx.games game and click the bookmark. If it worked, an alert will pop up. You can then head to the vega online editor and paste the JSON into the code box on the left. The editor will render the graph for you (if it doesn't, try clicking the Run button).