rumble, on records or from turntable?

Most rumble is from the table. The reason that it sounds louder on some records, is that some LPs are cut at a higher level than others, so you may be advancing your volume control to different points for different Lps which will affect the volume of the rumble. The London metro not withstanding.

To check TT rumble, test records are made with a "silent groove". I am sure that these test records are not perfect, so the "silent" groove really ought to be called the "as good as it gets" groove.

Many LPs do have LF rumble recorded into the grooves, and you can't do much about it unless you use a rumble filter. A common cause for this LF noise was the air conditioning systems in the recording halls. This was never a problem until the LF response of audio systems improved. When these LPs are played on a non-audiophile system there is no problem.

If I understand what you mean by "rumble" I think most of it can be attributed to the quality of the vinyl and also the pressing. You will hear less noise during the silent passages on quiet vinyl. If you have a quality pressing such as a Classic Records reissue (on Quiex vinyl), there shouldn't be an audible rumble in between tracks at reasonable volume levels. (Speakers Corner and Simply Vinyl reissues are also generally very quiet.) If you do hear the rumble on a record that is known to be quiet, then it could be caused by the cartridge, tonearm, platter, tt motor, or any combination thereof.

If you have a blank sided record you could play the blank side and listen. Shure made a test record years back that had a blank segment which could test the anti-skate mechanism of the tonearm.