Crontab to run a bash script that runs multiple python scripts

I'm a beginner in linux. I want run multiple python scripts every 30 second and I'm planning to do this using a bash script ( to run multiple python scripts simultaneously) and crontab (to schedule the scripts to run every 30 sec).

This is how my bash script:

#!/bin/bash
# This script is used to run multiple python script to query all types and all modes of GTFSR data

#Set working directory
cd "${0%/*}"

#BUS Query Real Time
python gtfsrdb_tfnsw.py -p 'https://api.transport.nsw.gov.au/v1/gtfs/vehiclepos/buses' --database="postgresql://localhost/test" —apikey="XXX" -m "buses" -c -1 &
python gtfsrdb_tfnsw.py -t 'https://api.transport.nsw.gov.au/v1/gtfs/realtime/buses' --database="postgresql://localhost/test" --apikey="XXX" -m "buses" -c -1 &
python gtfsrdb_tfnsw.py -a 'https://api.transport.nsw.gov.au/v1/gtfs/alerts/buses' --database="postgresql://localhost/test" --apikey="XXX" -m "buses" -c -1 &

#Sydney Train Real Time
python gtfsrdb_tfnsw.py -p 'https://api.transport.nsw.gov.au/v1/gtfs/vehiclepos/sydneytrains' --database="postgresql://localhost/test" --apikey="XXX" -m "sydneytrains" -c -1 &
python gtfsrdb_tfnsw.py -t 'https://api.transport.nsw.gov.au/v1/gtfs/realtime/sydneytrains' --database="postgresql://localhost/test" --apikey="XXX" -m "sydneytrains" -c -1 &
python gtfsrdb_tfnsw.py -a 'https://api.transport.nsw.gov.au/v1/gtfs/alerts/sydneytrains' --database="postgresql://localhost/test" --apikey="XXX" -m "sydneytrains" -c -1 &

#Ferries Real Time
python gtfsrdb_tfnsw.py -p 'https://api.transport.nsw.gov.au/v1/gtfs/vehiclepos/ferries' --database="postgresql://localhost/test" --apikey="XXX" -m "ferries" -c -1 &
python gtfsrdb_tfnsw.py -t 'https://api.transport.nsw.gov.au/v1/gtfs/realtime/ferries' --database="postgresql://localhost/test" --apikey="XXX" -m "ferries" -c -1 &
python gtfsrdb_tfnsw.py -a 'https://api.transport.nsw.gov.au/v1/gtfs/alerts/ferries' --database="postgresql://localhost/test" --apikey="XXX" -m "ferries" -c -1 &

#lightrail Real Time
python gtfsrdb_tfnsw.py -p 'https://api.transport.nsw.gov.au/v1/gtfs/vehiclepos/lightrail' --database="postgresql://localhost/test" --apikey="XXX" -m "lightrail" -c -1 &
python gtfsrdb_tfnsw.py -t 'https://api.transport.nsw.gov.au/v1/gtfs/realtime/lightrail' --database="postgresql://localhost/test" --apikey="XXX" -m "lightrail" -c -1 &
python gtfsrdb_tfnsw.py -a 'https://api.transport.nsw.gov.au/v1/gtfs/alerts/lightrail' --database="postgresql://localhost/test" --apikey="XXX" -m "lightrail" -c -1 &

#nswtrains Real Time
python gtfsrdb_tfnsw.py -p 'https://api.transport.nsw.gov.au/v1/gtfs/vehiclepos/nswtrains' --database="postgresql://localhost/test" --apikey="XXX" -m "nswtrains" -c -1 &
python gtfsrdb_tfnsw.py -t 'https://api.transport.nsw.gov.au/v1/gtfs/realtime/nswtrains' --database="postgresql://localhost/test" --apikey="XXX" -m "nswtrains" -c -1 &
python gtfsrdb_tfnsw.py -a 'https://api.transport.nsw.gov.au/v1/gtfs/alerts/nswtrains' --database="postgresql://localhost/test" --apikey="XXX" -m "nswtrains" -c -1 &

This is what I put in crontab:

# GTFSR to Database
* * * * * ( /bin/bash /home/amarinS/projects/TfNSW_GTFSRDB/GTFSR_call)
* * * * * ( sleep 30 ; /bin/bash /home/amarinS/projects/TfNSW_GTFSRDB/GTFSR_call)

If I run /bin/bash /home/amarinS/projects/TfNSW_GTFSRDB/GTFSR_call manually, the bash script works fine. However nothing happens when the job is run via CRONTAB.

Please help.

Cheers!