"EMD#Blomberg" 2Axle "B" bogie trucks first went into service in 1939 under the EMD#FT4Axle "B-B" locomotive series; the original "B" version plus later "M" and "X" versions were quite successful and became standard equipment on a multitude of locomotive models. They are easily identified by a prominent "swing hanger" on each side which widen the effective spring base and provide a better ride. EMD literature refers to this bogie truck as the "2Axle Outside Swing Hanger"; informally it is named after EMD designer Martin Blomberg; this design evolved as an abbreviation of the preceding EMD#BlombergA1A 3Axle design; see filed 1938Jan29 then granted 1940Feb06. As of this 2020 writing, EMD#BlombergB+M+X bogie trucks are common sights under operating locomotives in North America.
Blomberg B version
The "B"lomberg version is the original 1939 design. It has 56.50i 1.435m standard gaugewheel sets, 40.00i 1.016m tread diameters, 108.0i 2.743m wheel base, originally Hyatt#6.500x12 roller bearings allowing 65750Lb 29.82t AxleGRL and 350hp 262kw EMD#D7 trac motors with 62tAxleBull~15tMotorPinion gears allowing 65MpHr 105KpHr, and eight cast ironbrake shoes with four 45.00psi 310.3kpa cylinders. Typical rebuilds have 716hp 536kw EMD#D78 trac motors with transposed coils plus improved insulation, and occasionally upgraded APcGG#6.500x12 tapered bearings allowing 70000Lb 31.75t AxleGRL. EMD#BlombergB bogie trucks are seen on other makers locomotives; this occasionally resulted when buyers of new General Electric Universal series locomotives preferred trade-in EMD bogie trucks and|or motors, instead of GE standard equipment.
Blomberg M version
The version was introduced in 1972 with the EMD Dash2 locomotive series; it is also used on later EMD#GP50, EMD#GP60, EMD#F40, EMD#F59, MPI#MP32+MP36,... It has 56.50i 1.435m standard gauge wheel sets, 40.00i 1.016m tread diameters, 108.0i 2.743m wheel base, originally Hyatt#6.500x12 roller bearings allowing 65750Lb 29.82t AxleGRL and 716hp 536kw EMD#D77 trac motors with 59tAxleBull~15tMotorPinion gears allowing 102MpHr 164KpHr, four composite brake shoes with two 72.00psi 496.5kpa cylinders, and dampers over the right-fore plus left-rear bearings. Typical rebuilds have 716hp 536kw EMD#D78 trac motors with transposed coils plus improved insulation, and occasionally upgraded APcGG#6.500x12 tapered bearings allowing 70000Lb 31.75t AxleGRL.
Blomberg X version
The "X"press version was introduced in 2007 with the MPI#MP40+MP54 Xpress locomotive series; its formal model is MPI#2237; this version directly evolved from the BlombergM, but is longer and thus not rebuilt from older Blomberg frames. It has 56.50i 1.435m standard gauge wheel sets with 40.00i 1.016m tread diameters and a 4.000i 0.102m longer 112.0i 2.845m wheel base, APcGG#6.875x12 tapered bearings allowing 72000Lb 32.66t AxleGRL, 950hp 712kw EMD#D87 or 1200hp 899kw MPI#AC trac motors with 57tAxleBull~20tMotorPinion gears allowing 110MpHr 177KpHr, four composite brake shoes with two 72.00psi 496.5kpa cylinders, dampers over the right-fore plus left-rear bearings, bolster-frame dampers, and hybrid lam springs instead of steel leaf springs,
