Box with numbers at 30th street upper level

On the east end of one of the platforms at 30th street station I noticed a box affixed to a roof support that had a series of numbers 1-possibly 9. The numbers are made using round holes cut in metal to form the individual numbers. It appeared to be so designed to be lighted from behind. At no time did I see an lights on in the box. Anyone familiar with this box and what function does it serve? (I do have a photo, but I won't post unless know one is familiar with the item in question.)

this was discussed here: http://www.railroad.net/forums/viewtopi ... 72&t=25202" onclick="window.open(this.href);return false;

As far as I can tell, this is the current assignment of numbers at the (compass) east end:
1 - Suburban or Market East
2 - Norristown
3 - West Trenton
4 - Warminster
5 - Lansdale/Doylestown
6 - (not used?)
7 - Chestnut Hill East
8 - Fox Chase

West end:
1 - (don't know)
2 - Wilmington/Newark
3 - Media/Elwyn
4 - Airport
5 - Malvern/Thorndale
6 - Powelton Ave. (probably not needed?)
7 - Trenton
8 - Chestnut Hill West

So they only pretended to eliminate R numbers.

1 on the west end is probably cynwyd.

Forgot all about Cynwyd. They probably adopted 1 after they decided to use 6 for Powelton Ave.

These are the current designations.

NB:
1 Main Line Suburban to Wayne Electric
2 Norristown
3 West Trenton
4 Warminster
5 Lansdale / Doyle
6 Main Line trains terminating Wayne to Carmel
7 Hill East
8 Fox Chase

SB
0 Cynwyd
2 AMTRAK PW line
3 Elwyn
4 Airport
5 AMTRAK Harrisburg Line
6 not used
7 AMTRAK NYP Line
8 Hill West

so if there was a D form applying to Newtown Jct, would they light up a 6, or light up 3,4,5 and 8?

all ... since all of the 5 options would be affected by a D for NX.