I noticed that several of the bulbs in my shop fixtures were very dirty, so I removed them to clean them, and took pictures while I was at it.

I usually pull any oddball/rare lamps from service to save them as specimens.  The only exception to this is a Westinghouse 155V 6S6 lamp that I have in a night light.  I only use it because I have a bag of them.  Little feller has lasted well over a year so far.  Still running as I write this.

The nitelite you mention is it 155 volt rated or does the 155v mean something else? I ask because as far as I know 150 volt mains was last seen in Europe back in the 1960s so that would make it a really old lamp at least 50 years!

155V incandescent low wattage indicator lamps are sometimes used on 120V mains to increase lifetime. They were, I believe, used in some types of trains that ran on 145 volts, but I am not sure. Some are still available today and are sometimes marked as extra long life.

I had a 120V 6S6 lamp with a deformed base and it would not fit in any of my indicator switches but fit nicely in a night light. It lasted about 14 months and the filament broke (it was a PC night light). I shook the bulb slightly and the break reconnected. It lasted about another 14 months before breaking in several places. Now I use a standard 4w C7 and the light no longer reacts to itself (reflection from the soap bottles by the sink).

Some exit signs use 145V T6 incandescents at 120V.

A 155 volt indicator lamp would be the proper type to use in some utility switchgear. The bus is 130 vols DC nominal, but as the battery is being re-charged it would reach nearly 155 volts prior to being dropped to floating voltage to float the bank between cycles), plus on 120 volt circuits it would last longer.

Save those lamps, those look pretty old and will be rare soon. I was lucky enough to snag rare NOS ITT and Ken Rad mercs from being put into servect