Footplating and Testing a P7

My favorite Locomotive: ABB's P7

WAP 7 is a high speed locomotive developed by Chittaranjan Locomotive Works in collaboration with Adtranz/ABB. It is capable of hauling trains at speeds ranging between 140 and 160 km per hour and is now largely used by Northern Railways (NR), South Central Railways (SCR),Southern Railways (SR), Eastern Railways (ER), South East Central Railway (SECR), Central Railways (CR), West Central Railways(WCR). 180 locomotives in service as of November 2013.

Another feature of this locomotive is that it eliminates the need to have separate EOG sets for air-conditioning in long distance trains hence providing significant amount of savings on maintenance and running costs. This technology, called HOG or "Head On Generation", transfers electric power from the loco's pantograph to the coaches instead of "End on Generation" in which a Power Car equipped with diesel generator capable of generating adequate power of 3-phase 50-cycle 415V/750V AC (called as hotel load) is provided at either end of the train rake to supply power.

Technical Specifications:

Manufacturers	Chittaranjan Locomotive Works
Traction Motors	6FRA 6068 3-phase squirrel-cage induction motors (850 kW, 2180V, 1283/2484 rpm, *270/310A; Weight- 2100 kg, forced-air ventilation, axle-hung, nose-suspended; Torque 6330/7140Nm. *95% efficiency.)
Gear Ratio	72:20
Axle load	20.5t
Power	6350 HP
Wheel diameter	1092mm new, 1016mm worn
Wheelbase	15700mm
Bogies	Co-Co, Fabricated Flexicoil Mark IV bogies; bogie wheelbase 18500mm + 18500mm
Unsprung mass per axle	3.984t
Length over buffers	20562mm
Length over headstocks	19280mm
Body width	3152mmn
loco weight	123t
Cab length	2434mm
Pantograph locked down height	4255mm

My Views :-

With a maximum speed rating of 200 km/h (IR restricts it to 140 km/hr), the WAP-7 has the highest acceleration figures while hauling mail/express trains. The WAP-7 can also haul loads of 24-26 passenger coaches (1430-1550t) at 140 km/h per hour. It is also known to haul 18 heavyweight Air Conditioned coaches (1120t) in 1:40 inclines single-handedly. At a trial conducted by Indian Railways, it clocked a speed of 177 km/h. It is the most successful passenger locomotive in the Indian Railways portfolio after the WAP-4. It is used to haul premium trains like the Rajdhani Express and the Shatabdi Express apart from other regular mail/express trains.

The Control Panel

Driver Display Unit

The Driver Display provides 800x600 VGA graphic and works as a man machine interface. 

Made as a panel mount equipment, it uses 10.4” LCD TFT display. Various fault messages and system generated prompts are displayed on screen. Driver is able to navigate through the menu using dedicated function keys.

 USB drive facilitates data exchange. 
The unique feature of this display is that it retains the existing 4x40 character display format of the existing WAG 9/ WAP 7/ WAP 5 class of three phase locomotives of Indian Railways as well as provides a graphic mimic window in which various process variables can be seen by selecting pre-defined screens using function keys. The display has both MVB and RS422 interface.

WAP-7 locomotive can deliver 6000 HP with regenerative braking being one of its salient features. The regenerative braking is deployed on down gradients conserving energy to the tune of 30-35 percent. It has an inbuilt microprocessor based fault diagnostic system to make trouble shooting easier.

         

At Howrah Loco Shed.

 At 123t, it is much heavier than the 78t WAP-5. Intended to haul heavier, 26-coach passenger trains and passenger/parcel mixed trains. The first one, Navkiran, #30201, which was commissioned in 2000, is homed at Gomoh .

Initial models were rated at 6125hp total power and 33000 kgf (323kN) tractive effort. Modifications during continuing trials resulted in improved performance with the loco now yielding 6350hp total power and 36000 kgf (352.8kN) tractive effort. In the trial runs [7/02] the upgraded WAP-7 #30203 was shown able to take a 24-coach train to 110km/h in just 235 to 245 seconds (compare: 324 seconds for a WAP-5). Braking systems as in the WAP-5, with regenerative braking rated at 183kN in the first units and 260kN in the later ones.

Earlier trials with WAP-7 locos had yielded times around 390 seconds for the same test, which had cast doubts on the future of this loco class which was designed to perform better than the WAP-5. After some trials with the Prayagraj Exp. in early 2002, now [11/02] the WAP-7 is being used to haul the 24-coach rake of ER's Poorva Exp. and will presumably soon be used for other trains as well. Max. tested speed is 160km/h, rated for 140km/h.

Better performing variants of the WAP-7 have been under development [9/04]; changes are said to include higher capacity components (including the main transformer) to allow stall-free running on 1:100 gradients, and a higher tractive effort of 42000 kgf (411kN). Some of the units starting around #30212 are also thought to have some enhancements in comparison to the very first ones. [11/04] Other plans by CLW for this loco class are said to include the provision of IGBT control, greater automation of some control tasks, and in-cab signalling. MU operation possible with a maximum of two locos.

The WAP-7 appears to have returned to the older (WAM, earlier WAP) style of pantograph with a single collector bar instead of the double collector bar used for the WAG-9.

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