तमन्ना जहाज के सफर की... क्यों करूं मैं, दिन भर की खुशियाँ लम्हों मे बर्बाद क्यों करूं मैं। - Amir

Dear Harsh,
AM-92 is the Pantograph produced by Stone India Ltd for High Speed Locomotive of Indian Railways i.e WAP-5 & WAP-7. This Pantograph is Spring Operated Pantograph. Stone India Ltd is the Company which manufacture Pantograph of all Locomotives and Emus of Indian Railways. AM-92 is a reliable Pantograph for High Speed Loco which is produced in our Country. It is also to be noted here that all other Normal Locomotives like WAM-4/WAP-4/WAG-5/WAG-7/WAG-9 use AM-12 Pantograph which is also produced by Stone India Ltd. If you want to know the details of AM-12 Pantograph refer this Link:
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The Basic Structure of AM-12 and AM-92 is same just the Difference is in it's components as because AM-12 is for Normal Loco and EMU, whereas AM-92 is for High Speed Loco.
WBL 85 is a Completely Air Operated Pantograph. It is imported from outside. As this Pantograph is very costly so few WAP-5 have this Pantograph and rest WAP-5 & WAP-7 has India made AM-92 Pantograph.
Both Pantograph are GOOD. But WBL-85 is the best but as it is Costly so we use AM-92 in WAP-5 & WAP-7 which is also a Durable and Good Pantograph.
I have dedicated blog on this: Entry#1563010