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PRR I1sa Decapod Pack

This pack adds multiple variants of the Pennsylvania Railroad's I1s and I1sa Decapods. All feature lods for performance, dynamic weathering, random numbers, authentic sounds, functional marker lights, and where appropriate selectable class lights.

The I1s was was introduced in 1916, designed for efficiency in low-speed drag service using a "limited cutoff" design that allowed steam more time to expand in its huge cylinders. In heavy drag service the type could reach thermal efficiency of up to 8%. (quite good for a steam locomotive) After building 123 of the type in their own shops, the Pennsy was so pleased with the design that they placed an order with the Baldwin locomotive works for 100 more in 1922, and another for 375 in 1923. The I1s became the standard heavy freight locomotive of the standard railroad of the world, with 598 locomotives in the class. This was rather unique among American railroads where the 2-10-0 type was relatively rare.

Beginning in the 1930's the locomotives were upgraded to the I1sa standard. This involved extending the steam cutoff limit from 50% to 78%, allowing for even greater low speed tractive effort. The majority of the class was converted by the late 40's, though some remained as the unmodified I1s type.

While designed for low-speed drag service, the decapods were capable of speeds of up to 50mph. However, they were notoriously rough riding at these speeds. The type's massive tractive effort for its size also meant that it was prone to wheelslip if its power was applied too quickly. The combination of the sheer size of its boiler and cylinders, its harsh handling, and tempermental nature earned the type the nickname "hippo". The decapods were commonly double-headed on the heaviest trains, with another one or even two added to push on the rear on steeper grades such as the famous horsehoe curve.

The I1s remained the primary heavy freight type from their introduction through WWII and into the '50s. Many lasted until the end of steam power as a whole.

These locomotives can be found under the "multiple units", "steam" category in the buy menu. They also each have one passenger slot, which is not a bug. Both are a result of these locomotives supporting random numbering which allows for unique road numbers without cluttering up the buy menu or making you download additional textures.

• Top Speed: 50 mph
  
• Power: 3,863 hp
  
• Tractive Effort: 96,000 lbf (I1s), 102,027 lbf (I1sa)
  
• Weight: 295 tons, 314 tons, or 399 tons (depends on size of tender)
  
• Available: 1916-1957

• Pennsylvania Railroad - I1s with small 90F82 tender. Equipped with class lights. There are versions with each class light indication, off, white for "extra", or green for "section". 1916-1930
  
• Pennsylvania Railroad - I1s with medium 130F82A tender. Also equipped with class lights including lit versions. 1926-1935
  
• Pennsylvania Railroad - I1sa with small 90F82 tender with doghouse. 1930-1946
  
• Pennsylvania Railroad - I1sa with small 90F82 tender with hooded doghouse for electrified territory. 1935-1946
  
• Pennsylvania Railroad - I1sa with medium 130F82A tender with doghouse. 1935-1949
  
• Pennsylvania Railroad - I1sa with 210F82A "Coast-to-Coast" tender and "tombstone" style marker lights. 1942-1957
  
• Pennsylvania Railroad - Modernized I1sa with small 90F82 tender with doghouse. 1946-1957
  
• Pennsylvania Railroad - Modernized I1sa with small 90F82 tender with hooded doghouse. 1946-1957
  
• Pennsylvania Railroad - Modernized I1sa with small 90F82 tender with large semi-streamlined doghouse. 1946-1957
  
• Pennsylvania Railroad - Modernized I1sa with trainphone equipped 210F82A "Coast-to-Coast" tender. 1946-1957
  
• Pennsylvania Railroad - Modernized I1sa with medium 130F82A tender. 1953-1957
  
• Generic colorable version - 1916-1957

Tender sizes affect costs. Larger tenders have increased up-front costs, but slightly reduce maintenance cost to represent that fewer stops are needed to take on fuel and water. The difference is minor for the medium 130F82A tender, and more substantial for the huge 210F82A.