Dietz Inspector Lantern

Hoping others know more than I about lanterns. Dietz made an item called an inspectors lantern. The only ones I find for sale are quite expensive as they are quite old and collector items. Does anyone make a replica that might be cheaper to buy? Also did all railroads use these as I cannot find a reference that the D&RGW NG used them. Mostly Eastern RR's.

is the Dietz Manufacturing that makes non railroad lanterns now the same Dietz that made RR lanterns in the 19th century? Is there a preferred go-to railroad lantern site on the Web?

Thanks.
Craig Miller