it depends on how many cells, and hiw many TRX per cell.
you can pack roughly around 10 to 14 TRX per E1.
Each TRX uses 2 E1 timeslots (for user plane traffic)
Each cell uses 1 E1 timeslot (for control plane traffic)
EGPRS requires additional timeslots for optimal throughput, but if you can live with lower throughputs, then you don’t need to keep any specific EGPRS capacity on the E1.