Those Woodlands Nissan buses on service are cameos (except
TIB1254K), and they are interchangeable Nissan buses between
services 178, 187 and 981 too. The original perm buses are TIB658K,
TIB665P and TIB673R, like what vivienlee mentioned. it is just that
Woodlands always like to extract the Scanias from services 178, 187
and 980 to use them as "spares", then replace the original buses
with Nissans. Sounds very confusing... 
