Route 15 is where you will find older buses. If you want your last rides on the 81xx series, you better do it now. With Callowhill District now getting the new 36xx series NFXDE40s with BAEs on them, which is replacing the DE41LFs.
3000-3524 are 2017-2021 XDE40s
their current roster looks:
3000-3059 at Callowhill (10, 15, 21, 30, 31, 38, 40, 42, 44, 46, 52, 65)
3060-3084 at Victory (103-123, 125-126)
3085-3123 at Southern (G, 2, 4, 7, 17, 29, 37, 45, 47, 57, 64, 68, 79)
3124-3129, 3190-3229 at Frontier (90-99, 124, 127-133, 139, 150, 201, 206)
3130-3169 at Frankford (J, K, R, 1, 3, 5, 8, 19, 25, 67, 73, 88 {59, 66, 75} )
3170-3189 at Comly (BD, 1, 14, 19, 20, 24, 28, 50, 58, 67, 70, 78, 84, 88)
3230-3254, 3295-3344 at Midvale (H, L, XH, 2, 4, 16, 18, 22, 23, 26, 32, 35, 47, 53, 55, 56, 57, 61, 62, 77, 80, 89)
3255-3274 at Victory
3275-3294, 3345-3364 at Frankford
3365-3384 at Comly
3385-3409 at Callowhill
3410-3434 at Allegheny (6, 33, 48, 49, 54, 60)
3435-3454 at Southern
3455-3504 at Victory
3505-3524 at Frankford