Küstenstraßenbahn,

BN/ACEC type 6100 6-axle

Nr. 6145

The factory wanted to test normal-track bogies for the export of new trams to Manila and Portland. Because of the deviating gauge, these tests could only take place at night, and in Brussels.
The number wasn't added on the tram, but this is effectively the 6145.

Photo: Herbert Heller (Belgium) negative and photo from my collection and written permission to use the collection in my possession.