A transport refrigeration system comprising: a compressor; a heat rejection heat exchanger downstream of the compressor along a refrigerant primary flowpath; an expansion device downstream of the heat rejection heat exchanger along the refrigerant primary flowpath; and a heat absorption heat exchanger downstream of the expansion device along the refrigerant primary flowpath; and a single, combined economizer heat exchanger (57; 200; 300; 400; 500) between the heat rejection heat exchanger and the expansion device along the refrigerant primary flowpath and comprising: a first portion configured to provide heat transfer from the primary flowpath to a first economizer flowpath; and a second portion configured to provide heat transfer from the primary flowpath to a second economizer flowpath, and wherein the first and second economizer flowpaths branch from the primary flowpath from a location between the economizer heat exchanger and the expansion device; wherein: the compressor has a first cylinder, a second cylinder, and a third cylinder 32); the first economizer flowpath returns to the primary flowpath between the first and second cylinders and extends through: a second expansion device; and the economizer first portion; the second economizer flowpath returns to the primary flowpath between the second cylinder and the heat rejection heat exchanger and extends through: a third expansion device; the economizer second portion; and the third cylinder. a compressor; a heat rejection heat exchanger downstream of the compressor along a refrigerant primary flowpath; an expansion device downstream of the heat rejection heat exchanger along the refrigerant primary flowpath; and a heat absorption heat exchanger downstream of the expansion device along the refrigerant primary flowpath; and a single, combined economizer heat exchanger (57; 200; 300; 400; 500) between the heat rejection heat exchanger and the expansion device along the refrigerant primary flowpath and comprising: a first portion configured to provide heat transfer from the primary flowpath to a first economizer flowpath; and a second portion configured to provide heat transfer from the primary flowpath to a second economizer flowpath, and a first portion configured to provide heat transfer from the primary flowpath to a first economizer flowpath; and a second portion configured to provide heat transfer from the primary flowpath to a second economizer flowpath, and wherein the first and second economizer flowpaths branch from the primary flowpath from a location between the economizer heat exchanger and the expansion device; wherein: the compressor has a first cylinder, a second cylinder, and a third cylinder 32); the first economizer flowpath returns to the primary flowpath between the first and second cylinders and extends through: a second expansion device; and the economizer first portion; the second economizer flowpath returns to the primary flowpath between the second cylinder and the heat rejection heat exchanger and extends through: a third expansion device; the economizer second portion; and the third cylinder. the compressor has a first cylinder, a second cylinder, and a third cylinder 32); the first economizer flowpath returns to the primary flowpath between the first and second cylinders and extends through: a second expansion device; and the economizer first portion; a second expansion device; and the economizer first portion; the second economizer flowpath returns to the primary flowpath between the second cylinder and the heat rejection heat exchanger and extends through: a third expansion device; the economizer second portion; and the third cylinder. a third expansion device; the economizer second portion; and the third cylinder.