diff --git a/hw6/post.go b/hw6/post.go
index 6e1c4f5..f3951bc 100644
--- a/hw6/post.go
+++ b/hw6/post.go
@@ -10,12 +10,12 @@ func main() {
 	office := *post.NewSortOffice()
 
 	// Configure senders.
-	boxSender := func(p post.PackageI) {
+	boxSender := func(p post.Package) {
 		fmt.Println("BoxSender is sending " + p.PackageType() + " from " + p.SenderAddress() + " to " + p.RecepientAddress())
 	}
 	office.AddSender(post.BoxPackageType, boxSender)
 
-	envelopeSender := func(p post.PackageI) {
+	envelopeSender := func(p post.Package) {
 		fmt.Println("EnvelopeSender is sending " + p.PackageType() + " from " + p.SenderAddress() + " to " + p.RecepientAddress())
 	}
 	office.AddSender(post.EnvelopePackageType, envelopeSender)
diff --git a/hw6/post/package.go b/hw6/post/package.go
index d3a5660..28ff76a 100644
--- a/hw6/post/package.go
+++ b/hw6/post/package.go
@@ -4,13 +4,13 @@ const BoxPackageType = "box"
 const EnvelopePackageType = "envelope"
 
 // Package interface.
-type PackageI interface {
+type Package interface {
 	PackageType() string
 	SenderAddress() string
 	RecepientAddress() string
 }
 
-// box implementation of PackageI
+// box implementation of Package
 type box struct {
 }
 
@@ -28,7 +28,7 @@ func (b *box) RecepientAddress() string {
 	return "recepient address"
 }
 
-// Envelope implementation of PackageI
+// Envelope implementation of Package
 type Envelope struct {
 }
 
diff --git a/hw6/post/sortOffice.go b/hw6/post/sortOffice.go
index cd6d1bd..190c23b 100644
--- a/hw6/post/sortOffice.go
+++ b/hw6/post/sortOffice.go
@@ -4,23 +4,23 @@ import "errors"
 
 // Sorting office.
 type sortOffice struct {
-	senders map[string]func(PackageI)
+	senders map[string]func(Package)
 }
 
 // Sorting office constructor.
 func NewSortOffice() *sortOffice {
 	return &sortOffice{
-		senders: make(map[string]func(PackageI)),
+		senders: make(map[string]func(Package)),
 	}
 }
 
 // Add sender function for each package type.
-func (s *sortOffice) AddSender(packageType string, fn func(p PackageI)) {
+func (s *sortOffice) AddSender(packageType string, fn func(p Package)) {
 	s.senders[packageType] = fn
 }
 
 // Send package via configured sender function.
-func (s *sortOffice) Send(p PackageI) error {
+func (s *sortOffice) Send(p Package) error {
 	sendFn, ok := s.senders[p.PackageType()]
 
 	if !ok {
diff --git a/hw6/transport.go b/hw6/transport.go
index 365c9cb..cf56b24 100644
--- a/hw6/transport.go
+++ b/hw6/transport.go
@@ -8,9 +8,15 @@ import (
 func main() {
 	route := transport.NewRoute()
 
-	car := transport.NewCar()
-	train := transport.NewTrain()
-	plane := transport.NewPlane()
+	car := transport.NewCar(4)
+	_ = car.TakePassengers(transport.NewPassenger())
+	_ = car.TakePassengers(transport.NewPassenger())
+
+	train := transport.NewTrain(200)
+
+	planeRegistration := transport.NewRegistration()
+	planeRegistration.AddPassengers(transport.NewPassenger())
+	plane := transport.NewPlane(planeRegistration)
 
 	route.AddTransport(car)
 	route.AddTransport(train)
diff --git a/hw6/transport/car.go b/hw6/transport/car.go
index e228f60..6e668b6 100644
--- a/hw6/transport/car.go
+++ b/hw6/transport/car.go
@@ -1,9 +1,17 @@
 package transport
 
-type Car struct{}
+import (
+	"errors"
+	"strconv"
+)
+
+type Car struct {
+	maxPassengers int
+	passengers    []*passenger
+}
 
-func NewCar() *Car {
-	return &Car{}
+func NewCar(maxPassengers int) *Car {
+	return &Car{maxPassengers: maxPassengers}
 }
 
 func (c *Car) Name() string {
@@ -18,12 +26,17 @@ func (c *Car) Stop() {
 	println("Car stopped")
 }
 
-func (c *Car) ChangeSpeed() {
+func (c *Car) ChangeSpeed(int) error {
 	println("Car changed speed")
+	return nil
 }
 
-func (c *Car) TakePassengers() {
-	println("Car took passengers")
+func (c *Car) TakePassengers(p *passenger) error {
+	if len(c.passengers) == c.maxPassengers {
+		return errors.New("Cannot take more than " + strconv.Itoa(c.maxPassengers))
+	}
+	c.passengers = append(c.passengers, p)
+	return nil
 }
 
 func (c *Car) DropPassengers() {
diff --git a/hw6/transport/passenger.go b/hw6/transport/passenger.go
new file mode 100644
index 0000000..ba5b35e
--- /dev/null
+++ b/hw6/transport/passenger.go
@@ -0,0 +1,7 @@
+package transport
+
+type passenger struct{}
+
+func NewPassenger() *passenger {
+	return &passenger{}
+}
diff --git a/hw6/transport/plane.go b/hw6/transport/plane.go
index 37e5834..d99a1ec 100644
--- a/hw6/transport/plane.go
+++ b/hw6/transport/plane.go
@@ -1,6 +1,15 @@
 package transport
 
-type plane struct{}
+import "errors"
+
+type plane struct {
+	registration *registration
+	passengers   []*passenger
+}
+
+func NewPlane(registration *registration) *plane {
+	return &plane{registration: registration}
+}
 
 func (p *plane) Name() string {
 	return "Plane"
@@ -14,17 +23,29 @@ func (p *plane) Stop() {
 	println("Plane stopped")
 }
 
-func (p *plane) ChangeSpeed() {
+func (p *plane) ChangeSpeed(int) error {
 	println("Plane changed speed")
+	return nil
 }
 
-func (p *plane) TakePassengers() {
-	println("Plane took passengers")
+func (pl *plane) TakePassengers(p *passenger) error {
+	// Check if passenger is in registration list.
+	found := false
+	for _, pr := range pl.registration.passengers {
+		if p == pr {
+			found = true
+		}
+	}
+
+	if !found {
+		return errors.New("passenger not found in registration")
+	}
+
+	pl.passengers = append(pl.passengers, p)
+
+	return nil
 }
 
 func (p *plane) DropPassengers() {
 	println("Plane dropped passengers")
 }
-func NewPlane() *plane {
-	return &plane{}
-}
diff --git a/hw6/transport/registration.go b/hw6/transport/registration.go
new file mode 100644
index 0000000..ba27698
--- /dev/null
+++ b/hw6/transport/registration.go
@@ -0,0 +1,13 @@
+package transport
+
+type registration struct {
+	passengers []*passenger
+}
+
+func NewRegistration() *registration {
+	return &registration{}
+}
+
+func (r *registration) AddPassengers(p *passenger) {
+	r.passengers = append(r.passengers, p)
+}
diff --git a/hw6/transport/route.go b/hw6/transport/route.go
index 477ec6f..f6f9448 100644
--- a/hw6/transport/route.go
+++ b/hw6/transport/route.go
@@ -1,14 +1,14 @@
 package transport
 
 type route struct {
-	transport []TransportI
+	transport []Transport
 }
 
 func NewRoute() *route {
 	return &route{}
 }
 
-func (r *route) AddTransport(t TransportI) {
+func (r *route) AddTransport(t Transport) {
 	r.transport = append(r.transport, t)
 }
 
diff --git a/hw6/transport/train.go b/hw6/transport/train.go
index 84ab2cc..e0c4d1b 100644
--- a/hw6/transport/train.go
+++ b/hw6/transport/train.go
@@ -1,9 +1,17 @@
 package transport
 
-type train struct{}
+import (
+	"errors"
+	"strconv"
+)
+
+type train struct {
+	maxSpeed int
+	speed    int
+}
 
-func NewTrain() *train {
-	return &train{}
+func NewTrain(maxSpeed int) *train {
+	return &train{maxSpeed: maxSpeed}
 }
 
 func (t *train) Name() string {
@@ -18,12 +26,20 @@ func (t *train) Stop() {
 	println("Train stopped")
 }
 
-func (t *train) ChangeSpeed() {
-	println("Train changed speed")
+func (t *train) ChangeSpeed(speedChange int) error {
+	newSpeed := t.speed + speedChange
+
+	if newSpeed > t.maxSpeed {
+		return errors.New("speed is over max: " + strconv.Itoa(t.maxSpeed))
+	}
+
+	t.speed = newSpeed
+	return nil
 }
 
-func (t *train) TakePassengers() {
+func (t *train) TakePassengers(*passenger) error {
 	println("Train took passengers")
+	return nil
 }
 
 func (t *train) DropPassengers() {
diff --git a/hw6/transport/transport.go b/hw6/transport/transport.go
new file mode 100644
index 0000000..1c40719
--- /dev/null
+++ b/hw6/transport/transport.go
@@ -0,0 +1,11 @@
+package transport
+
+// Transport interface.
+type Transport interface {
+	Name() string
+	Move()
+	Stop()
+	ChangeSpeed(speedChange int) error
+	TakePassengers(p *passenger) error
+	DropPassengers()
+}
diff --git a/hw6/transport/transportI.go b/hw6/transport/transportI.go
deleted file mode 100644
index 4aa26cc..0000000
--- a/hw6/transport/transportI.go
+++ /dev/null
@@ -1,11 +0,0 @@
-package transport
-
-// TransportI interface.
-type TransportI interface {
-	Name() string
-	Move()
-	Stop()
-	ChangeSpeed()
-	TakePassengers()
-	DropPassengers()
-}